A GoogleSQL statement comprises a series of tokens. Tokens include
identifiers, quoted identifiers, literals, keywords, operators, and
special characters. You can separate tokens with comments or whitespace such
as spaces, backspaces, tabs, or newlines.

## Identifiers

Identifiers are names that are associated with columns, tables,
fields, path expressions, and more. They can be
[unquoted](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#unquoted_identifiers) or [quoted](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#quoted_identifiers) and some
are [case-sensitive](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#case_sensitivity).

### Unquoted identifiers

- Must begin with a letter or an underscore (_) character.
- Subsequent characters can be letters, numbers, or underscores (_).

### Quoted identifiers

- Must be enclosed by backtick (\`) characters.
- Can't be empty.
- Have the same escape sequences as [string literals](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#string_and_bytes_literals).
- If an identifier is the same as a [reserved keyword](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#reserved_keywords), the identifier must be quoted. For example, the identifier `FROM` must be quoted. Additional rules apply for [path expressions](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#path_expressions) , [table names](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#table_names), [column names](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#column_names), and [field names](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#field_names).

### Identifier examples

Path expression examples:

    -- Valid. _5abc and dataField are valid identifiers.
    _5abc.dataField

    -- Valid. `5abc` and dataField are valid identifiers.
    `5abc`.dataField

    -- Invalid. 5abc is an invalid identifier because it's unquoted and starts
    -- with a number rather than a letter or underscore.
    5abc.dataField

    -- Valid. abc5 and dataField are valid identifiers.
    abc5.dataField

    -- Invalid. abc5! is an invalid identifier because it's unquoted and contains
    -- a character that isn't a letter, number, or underscore.
    abc5!.dataField

    -- Valid. `GROUP` and dataField are valid identifiers.
    `GROUP`.dataField

    -- Invalid. GROUP is an invalid identifier because it's unquoted and is a
    -- stand-alone reserved keyword.
    GROUP.dataField

    -- Valid. abc5 and GROUP are valid identifiers.
    abc5.GROUP

Function examples:

    -- Valid. dataField is a valid identifier in a function called foo().
    foo().dataField

Array access operation examples:

    -- Valid. dataField is a valid identifier in an array called items.
    items[OFFSET(3)].dataField

Named query parameter examples:

    -- Valid. param and dataField are valid identifiers.
    @param.dataField

Table name examples:

    -- Valid table path.
    myproject.mydatabase.mytable287

    -- Valid table path.
    myproject287.mydatabase.mytable

    -- Invalid table path. The project name starts with a number and is unquoted.
    287myproject.mydatabase.mytable

    -- Invalid table name. The table name is unquoted and isn't a valid
    -- dashed identifier, as the part after the dash is neither a number nor
    -- an identifier starting with a letter or an underscore.
    mytable-287a

    -- Valid table path.
    my-project.mydataset.mytable

    -- Valid table name.
    my-table

    -- Invalid table path because the dash isn't in the first part
    -- of the path.
    myproject.mydataset.my-table

    -- Invalid table path because a dataset name can't contain dashes.
    my-dataset.mytable

## Path expressions

A path expression describes how to navigate to an object in a graph of objects
and generally follows this structure:

    path:
      [path_expression][. ...]

    path_expression:
      [first_part]/subsequent_part[ { / | : | - } subsequent_part ][...]

    first_part:
      { unquoted_identifier | quoted_identifier }

    subsequent_part:
      { unquoted_identifier | quoted_identifier | number }

- `path`: A graph of one or more objects.
- `path_expression`: An object in a graph of objects.
- `first_part`: A path expression can start with a quoted or unquoted identifier. If the path expressions starts with a [reserved keyword](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#reserved_keywords), it must be a quoted identifier.
- `subsequent_part`: Subsequent parts of a path expression can include non-identifiers, such as reserved keywords. If a subsequent part of a path expressions starts with a [reserved keyword](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#reserved_keywords), it may be quoted or unquoted.

Examples:

    foo.bar
    foo.bar/25
    foo/bar:25
    foo/bar/25-31
    /foo/bar
    /25/foo/bar

## Table names

A table name represents the name of a table.

- Table names can be quoted identifiers or unquoted identifiers.
- A table name that's an unquoted identifier can additionally include single dashes if the table name is referenced in a `FROM` or `TABLE` clause. Only the first identifier in the table path (the project ID or the table name) can have dashes. Dashes aren't supported in datasets.
- A table name can be a
  [fully qualified table name (table path)](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#table_path)
  that includes up to three quoted or unquoted identifiers:

  - An optional [project ID](https://docs.cloud.google.com/resource-manager/docs/creating-managing-projects#before_you_begin)

  - An optional [dataset name](https://docs.cloud.google.com/bigquery/docs/datasets#dataset-naming)

  - A required table name.

  For example: `myproject.mydataset.mytable`
- Table names can be path expressions.

- Table names have [case-sensitivity rules](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#case_sensitivity).

- Table names have [additional rules](https://docs.cloud.google.com/bigquery/docs/tables#table_naming).

Examples:

    my-project.mydataset.mytable
    mydataset.mytable
    my-table
    mytable
    `287mytable`

## Column names

A column name represents the name of a column in a table. Column names can be
quoted identifiers or unquoted identifiers. Column names also
have [additional rules](https://docs.cloud.google.com/bigquery/docs/schemas#column_names).

Examples:

    columnA
    `column-a`
    `287column`

## Field names

A field name represents the name of a field inside a complex data type such
as a struct or
JSON object.

- A field name can be a quoted identifier or an unquoted identifier.
- Field names must adhere to all of the rules for column names.

## Literals

A literal represents a constant value of a built-in data type. Some, but not
all, data types can be expressed as literals.

### String and bytes literals

A string literal represents a constant value of the
[string data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#string_type). A bytes literal represents a
constant value of the [bytes data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#bytes_type).

Both string and bytes literals must be *quoted* , either with single (`'`) or
double (`"`) quotation marks, or *triple-quoted* with groups of three single
(`'''`) or three double (`"""`) quotation marks.

#### Formats for quoted literals

The following table lists all of the ways you can format a quoted literal.

| Literal | Examples | Description |
|---|---|---|
| Quoted string | - `"abc"` - `"it's"` - `'it\'s'` - `'Title: "Boy"'` | Quoted strings enclosed by single (`'`) quotes can contain unescaped double (`"`) quotes, as well as the inverse. Backslashes (`\`) introduce escape sequences. See the Escape Sequences table below. Quoted strings can't contain newlines, even when preceded by a backslash (`\`). |
| Triple-quoted string | - `"""abc"""` - `'''it's'''` - `'''Title:"Boy"'''` - `'''two lines'''` - `'''why\?'''` | Embedded newlines and quotes are allowed without escaping - see fourth example. Backslashes (`\`) introduce escape sequences. See Escape Sequences table below. A trailing unescaped backslash (`\`) at the end of a line isn't allowed. End the string with three unescaped quotes in a row that match the starting quotes. |
| Raw string | - `r"abc+"` - `r'''abc+'''` - `r"""abc+"""` - `r'f\(abc,(.*),def\)'` | Quoted or triple-quoted literals that have the raw string literal prefix (`r` or `R`) are interpreted as raw strings (sometimes described as regex strings). Backslash characters (`\`) don't act as escape characters. If a backslash followed by another character occurs inside the string literal, both characters are preserved. A raw string can't end with an odd number of backslashes. Raw strings are useful for constructing regular expressions. The prefix is case-insensitive. |
| Bytes | - `B"abc"` - `B'''abc'''` - `b"""abc"""` | Quoted or triple-quoted literals that have the bytes literal prefix (`b` or `B`) are interpreted as bytes. |
| Raw bytes | - `br'abc+'` - `RB"abc+"` - `RB'''abc'''` | A bytes literal can be interpreted as raw bytes if both the `r` and `b` prefixes are present. These prefixes can be combined in any order and are case-insensitive. For example, `rb'abc*'` and `rB'abc*'` and `br'abc*'` are all equivalent. See the description for raw string to learn more about what you can do with a raw literal. |

Like in many other languages, such as Python and C++, you can divide a
GoogleSQL string or bytes literal into chunks, each with its own quoting
or raw specification. The literal value is the concatenation of all these parts.

This is useful for a variety of purposes, including readability, organization,
formatting and maintainability, for example:

- You can break a literal into multiple chunks fit into a width of 80 characters.
- You can break a literal into chunks of different quotings and raw specifications to avoid escaping. For example, a string value inside a `JSON` string.
- You can change only one part of a literal through a macro, while the rest of the literal is unchanged.
- You can use string literal concatenation in other literals that include strings such as `DATE`, `TIMESTAMP`, `JSON`, etc.

The following restrictions apply to these literal concatenations:

- You can't mix string and byte literals.
- You must ensure there is some separation between the concatenated parts, such as whitespace or comments.
- `r` specifiers apply only to the immediate chunk, not the rest of the literal parts.
- Quoted identifiers don't concatenate.

Examples:

| Literals divided into chunks | Equivalent literals |
|---|---|
| SELECT r'\n' /*Only the prev is raw!*/ '\n' "b" """c"d"e""" '''f'g'h''' "1" "2", br'\n'/*Only the prev is raw!*/ b'\n' b"b" b"""c"d"e""" b'''f'g'h''' b"1" b"2", NUMERIC "1" r'2', DECIMAL /*whole:*/ '1' /*fractional:*/ ".23" /*exponent=*/ "e+6", BIGNUMERIC '1' r"2", BIGDECIMAL /*sign*/ '-' /*whole:*/ '1' /*fractional:*/ ".23" /*exponent=*/ "e+6", RANGE<DATE> '[2014-01-01,' /*comment*/ "2015-01-01)", DATE '2014' "-01-01", DATETIME '2016-01-01 ' r"12:00:00", TIMESTAMP '2018-10-01 ' "12:00:00+08" | SELECT "\\n\nbc\"d\"ef'g'h12", b"\\n\nbc\"d\"ef'g'h12", NUMERIC "12", DECIMAL '1.23e+6', BIGNUMERIC '12', BIGDECIMAL "-1.23e+6", RANGE<DATE> '[2014-01-01 2015-01-01)', DATE '2014-01-01', DATETIME '2016-01-01 12:00:00', TIMESTAMP "2018-10-01 12:00:00+08" |

#### Escape sequences for string and bytes literals

The following table lists all valid escape sequences for representing
non-alphanumeric characters in string and bytes literals. Any sequence not in
this table produces an error.

| Escape Sequence | Description |
|---|---|
| `\a` | Bell |
| `\b` | Backspace |
| `\f` | Formfeed |
| `\n` | Newline |
| `\r` | Carriage Return |
| `\t` | Tab |
| `\v` | Vertical Tab |
| `\\` | Backslash (`\`) |
| `\?` | Question Mark (`?`) |
| `\"` | Double Quote (`"`) |
| `\'` | Single Quote (`'`) |
| `` \` `` | Backtick (`` ` ``) |
| `\ooo` | Octal escape, with exactly 3 digits (in the range 0--7). Decodes to a single Unicode character (in string literals) or byte (in bytes literals). |
| `\xhh` or `\Xhh` | Hex escape, with exactly 2 hex digits (0--9 or A--F or a--f). Decodes to a single Unicode character (in string literals) or byte (in bytes literals). Examples: - `'\x41'` == `'A'` - `'\x41B'` is `'AB'` - `'\x4'` is an error |
| `\uhhhh` | Unicode escape, with lowercase 'u' and exactly 4 hex digits. Valid only in string literals or identifiers. Note that the range D800-DFFF isn't allowed, as these are surrogate unicode values. |
| `\Uhhhhhhhh` | Unicode escape, with uppercase 'U' and exactly 8 hex digits. Valid only in string literals or identifiers. The range D800-DFFF isn't allowed, as these values are surrogate unicode values. Also, values greater than 10FFFF aren't allowed. |

### Integer literals

Integer literals are either a sequence of decimal digits (0--9) or a hexadecimal
value that's prefixed with "`0x`" or "`0X`". Integers can be prefixed by "`+`"
or "`-`" to represent positive and negative values, respectively.
Examples:

    123
    0xABC
    -123

An integer literal is interpreted as an `INT64`.

A integer literal represents a constant value of the
[integer data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#integer_types).

### `NUMERIC` literals

You can construct `NUMERIC` literals using the
`NUMERIC` keyword followed by a floating point value in quotes.

Examples:

    SELECT NUMERIC '0';
    SELECT NUMERIC '123456';
    SELECT NUMERIC '-3.14';
    SELECT NUMERIC '-0.54321';
    SELECT NUMERIC '1.23456e05';
    SELECT NUMERIC '-9.876e-3';

A `NUMERIC` literal represents a constant value of the
[`NUMERIC` data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#decimal_types).

### `BIGNUMERIC` literals

You can construct `BIGNUMERIC` literals using the `BIGNUMERIC` keyword followed
by a floating point value in quotes.

Examples:

    SELECT BIGNUMERIC '0';
    SELECT BIGNUMERIC '123456';
    SELECT BIGNUMERIC '-3.14';
    SELECT BIGNUMERIC '-0.54321';
    SELECT BIGNUMERIC '1.23456e05';
    SELECT BIGNUMERIC '-9.876e-3';

A `BIGNUMERIC` literal represents a constant value of the
[`BIGNUMERIC` data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#decimal_types).

### Floating point literals

Syntax options:

    [+-]DIGITS.[DIGITS][e[+-]DIGITS]
    [+-][DIGITS].DIGITS[e[+-]DIGITS]
    DIGITSe[+-]DIGITS

`DIGITS` represents one or more decimal numbers (0 through 9) and `e` represents
the exponent marker (e or E).

Examples:

    123.456e-67
    .1E4
    58.
    4e2

Numeric literals that contain
either a decimal point or an exponent marker are presumed to be type double.

Implicit coercion of floating point literals to float type is possible if the
value is within the valid float range.

There is no literal
representation of NaN or infinity, but the following case-insensitive strings
can be explicitly cast to float:

- "NaN"
- "inf" or "+inf"
- "-inf"

A floating-point literal represents a constant value of the
[floating-point data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#floating_point_types).

### Array literals

Array literals are comma-separated lists of elements
enclosed in square brackets. The `ARRAY` keyword is optional, and an explicit
element type T is also optional.

Examples:

    [1, 2, 3]
    ['x', 'y', 'xy']
    ARRAY[1, 2, 3]
    ARRAY<STRING>['x', 'y', 'xy']
    ARRAY<INT64>[]

An array literal represents a constant value of the
[array data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#array_type).

### Struct literals

A struct literal is a struct whose fields are all literals. Struct literals can
be written using any of the syntaxes for [constructing a
struct](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#constructing_a_struct) (tuple syntax, typeless struct syntax, or typed
struct syntax).

Note that tuple syntax requires at least two fields, in order to distinguish it
from an ordinary parenthesized expression. To write a struct literal with a
single field, use typeless struct syntax or typed struct syntax.

| Example | Output Type |
|---|---|
| `(1, 2, 3)` | `STRUCT<INT64, INT64, INT64>` |
| `(1, 'abc')` | `STRUCT<INT64, STRING>` |
| `STRUCT(1 AS foo, 'abc' AS bar)` | `STRUCT<foo INT64, bar STRING>` |
| `STRUCT<INT64, STRING>(1, 'abc')` | `STRUCT<INT64, STRING>` |
| `STRUCT(1)` | `STRUCT<INT64>` |
| `STRUCT<INT64>(1)` | `STRUCT<INT64>` |

A struct literal represents a constant value of the
[struct data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#struct_type).

### Date literals

Syntax:

    DATE 'date_canonical_format'

Date literals contain the `DATE` keyword followed by
[`date_canonical_format`](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#canonical_format_for_date_literals),
a string literal that conforms to the canonical date format, enclosed in single
quotation marks. Date literals support a range between the
years 1 and 9999, inclusive. Dates outside of this range are invalid.

For example, the following date literal represents September 27, 2014:

    DATE '2014-09-27'

String literals in canonical date format also implicitly coerce to DATE type
when used where a DATE-type expression is expected. For example, in the query

    SELECT * FROM foo WHERE date_col = "2014-09-27"

the string literal `"2014-09-27"` will be coerced to a date literal.

A date literal represents a constant value of the
[date data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#date_type).

### Time literals

Syntax:

    TIME 'time_canonical_format'

Time literals contain the `TIME` keyword and
[`time_canonical_format`](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#canonical_format_for_time_literals), a string literal that conforms to
the canonical time format, enclosed in single quotation marks.

For example, the following time represents 12:30 p.m.:

    TIME '12:30:00.45'

A time literal represents a constant value of the
[time data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#time_type).

### Datetime literals

Syntax:

    DATETIME 'datetime_canonical_format'

Datetime literals contain the `DATETIME` keyword and
[`datetime_canonical_format`](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#canonical_format_for_datetime_literals), a string literal that
conforms to the canonical datetime format, enclosed in single quotation marks.

For example, the following datetime represents 12:30 p.m. on September 27,
2014:

    DATETIME '2014-09-27 12:30:00.45'

Datetime literals support a range between the years 1 and 9999, inclusive.
Datetimes outside of this range are invalid.

String literals with the canonical datetime format implicitly coerce to a
datetime literal when used where a datetime expression is expected.

For example:

    SELECT * FROM foo
    WHERE datetime_col = "2014-09-27 12:30:00.45"

In the query above, the string literal `"2014-09-27 12:30:00.45"` is coerced to
a datetime literal.

A datetime literal can also include the optional character `T` or `t`. If
you use this character, a space can't be included before or after it.
These are valid:

    DATETIME '2014-09-27T12:30:00.45'
    DATETIME '2014-09-27t12:30:00.45'

A datetime literal represents a constant value of the
[datatime data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#datetime_type).

### Timestamp literals

Syntax:

    TIMESTAMP 'timestamp_canonical_format'

Timestamp literals contain the `TIMESTAMP` keyword and
[`timestamp_canonical_format`](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#canonical_format_for_timestamp_literals), a string literal that
conforms to the canonical timestamp format, enclosed in single quotation marks.

Timestamp literals support a range between the years 1 and 9999, inclusive.
Timestamps outside of this range are invalid.

A timestamp literal can include a numerical suffix to indicate the time zone:

    TIMESTAMP '2014-09-27 12:30:00.45-08'

If this suffix is absent, the default time zone,
UTC, is used.

For example, the following timestamp represents 12:30 p.m. on September 27,
2014 in the default time zone, UTC:

    TIMESTAMP '2014-09-27 12:30:00.45'

For more information about time zones, see [Time zone](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#timezone).

String literals with the canonical timestamp format, including those with
time zone names, implicitly coerce to a timestamp literal when used where a
timestamp expression is expected. For example, in the following query, the
string literal `"2014-09-27 12:30:00.45 America/Los_Angeles"` is coerced
to a timestamp literal.

    SELECT * FROM foo
    WHERE timestamp_col = "2014-09-27 12:30:00.45 America/Los_Angeles"

A timestamp literal can include these optional characters:

- `T` or `t`
- `Z` or `z`

If you use one of these characters, a space can't be included before or after
it. These are valid:

    TIMESTAMP '2017-01-18T12:34:56.123456Z'
    TIMESTAMP '2017-01-18t12:34:56.123456'
    TIMESTAMP '2017-01-18 12:34:56.123456z'
    TIMESTAMP '2017-01-18 12:34:56.123456Z'

A timestamp literal represents a constant value of the
[timestamp data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#timestamp_type).

#### Time zone

Since timestamp literals must be mapped to a specific point in time, a time zone
is necessary to correctly interpret a literal. If a time zone isn't specified
as part of the literal itself, then GoogleSQL uses the default time zone
value, which the GoogleSQL implementation sets.

GoogleSQL can represent a time zones using a string, which represents
the [offset from Coordinated Universal Time (UTC)](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#utc_offset).

Examples:

    '-08:00'
    '-8:15'
    '+3:00'
    '+07:30'
    '-7'

Time zones can also be expressed using string
[time zone names](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#time_zone_name).

Examples:

    TIMESTAMP '2014-09-27 12:30:00 America/Los_Angeles'
    TIMESTAMP '2014-09-27 12:30:00 America/Argentina/Buenos_Aires'

### Range literals

Syntax:

    RANGE<T> '[lower_bound, upper_bound)'

A range literal contains a contiguous range between two
[dates](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#date_type), [datetimes](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#datetime_type), or
[timestamps](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#timestamp_type). The lower or upper bound can be unbounded,
if desired.

Example of a date range literal with a lower and upper bound:

    RANGE<DATE> '[2020-01-01, 2020-12-31)'

Example of a datetime range literal with a lower and upper bound:

    RANGE<DATETIME> '[2020-01-01 12:00:00, 2020-12-31 12:00:00)'

Example of a timestamp range literal with a lower and upper bound:

    RANGE<TIMESTAMP> '[2020-10-01 12:00:00+08, 2020-12-31 12:00:00+08)'

Examples of a range literal without a lower bound:

    RANGE<DATE> '[UNBOUNDED, 2020-12-31)'

    RANGE<DATE> '[NULL, 2020-12-31)'

Examples of a range literal without an upper bound:

    RANGE<DATE> '[2020-01-01, UNBOUNDED)'

    RANGE<DATE> '[2020-01-01, NULL)'

Examples of a range literal that includes all possible values:

    RANGE<DATE> '[UNBOUNDED, UNBOUNDED)'

    RANGE<DATE> '[NULL, NULL)'

There must be a single whitespace after the comma in a range literal, otherwise
an error is produced. For example:

    -- This range literal is valid:
    RANGE<DATE> '[2020-01-01, 2020-12-31)'

    -- This range literal produces an error:
    RANGE<DATE> '[2020-01-01,2020-12-31)'

A range literal represents a constant value of the
[range data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#range_type).

### Interval literals

An interval literal represents a constant value of the
[interval data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#interval_type). There are two types of
interval literals:

- [Interval literal with a single datetime part](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#interval_literal_single)
- [Interval literal with a datetime part range](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#interval_literal_range)

An interval literal can be used directly inside of the `SELECT` statement
and as an argument in some functions that support the interval data type.

#### Interval literal with a single datetime part

Syntax:

    INTERVAL step_size step_unit

The single datetime part syntax includes an `INT64` expression and a
single [interval-supported datetime part](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#interval_datetime_parts).
For example:

    -- 0 years, 0 months, 5 days, 0 hours, 0 minutes, 0 seconds (0-0 5 0:0:0)
    INTERVAL 5 DAY

    -- 0 years, 0 months, -5 days, 0 hours, 0 minutes, 0 seconds (0-0 -5 0:0:0)
    INTERVAL -5 DAY

    -- 0 years, 0 months, 0 days, 0 hours, 0 minutes, 1 seconds (0-0 0 0:0:1)
    INTERVAL 1 SECOND

When a negative sign precedes the year or month part in an interval literal, the
negative sign distributes over the years and months. Or, when a negative sign
precedes the time part in an interval literal, the negative sign distributes
over the hours, minutes, and seconds. For example:

    -- -2 years, -1 months, 0 days, 0 hours, 0 minutes, and 0 seconds (-2-1 0 0:0:0)
    INTERVAL -25 MONTH

    -- 0 years, 0 months, 0 days, -1 hours, -30 minutes, and 0 seconds (0-0 0 -1:30:0)
    INTERVAL -90 MINUTE

For more information on how to construct interval with a single datetime part,
see [Construct an interval with a single datetime part](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#single_datetime_part_interval).

#### Interval literal with a datetime part range

Syntax:

    INTERVAL datetime_parts_string starting_datetime_part TO ending_datetime_part

The range datetime part syntax includes a
[datetime parts string](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#range_datetime_part_interval),
a [starting datetime part](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#interval_datetime_parts), and an
[ending datetime part](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#interval_datetime_parts).

For example:

    -- 0 years, 0 months, 0 days, 10 hours, 20 minutes, 30 seconds (0-0 0 10:20:30.520)
    INTERVAL '10:20:30.52' HOUR TO SECOND

    -- 1 year, 2 months, 0 days, 0 hours, 0 minutes, 0 seconds (1-2 0 0:0:0)
    INTERVAL '1-2' YEAR TO MONTH

    -- 0 years, 1 month, -15 days, 0 hours, 0 minutes, 0 seconds (0-1 -15 0:0:0)
    INTERVAL '1 -15' MONTH TO DAY

    -- 0 years, 0 months, 1 day, 5 hours, 30 minutes, 0 seconds (0-0 1 5:30:0)
    INTERVAL '1 5:30' DAY TO MINUTE

When a negative sign precedes the year or month part in an interval literal, the
negative sign distributes over the years and months. Or, when a negative sign
precedes the time part in an interval literal, the negative sign distributes
over the hours, minutes, and seconds. For example:

    -- -23 years, -2 months, 10 days, -12 hours, -30 minutes, and 0 seconds (-23-2 10 -12:30:0)
    INTERVAL '-23-2 10 -12:30' YEAR TO MINUTE

    -- -23 years, -2 months, 10 days, 0 hours, -30 minutes, and 0 seconds (-23-2 10 -0:30:0)
    SELECT INTERVAL '-23-2 10 -0:30' YEAR TO MINUTE

    -- Produces an error because the negative sign for minutes must come before the hour.
    SELECT INTERVAL '-23-2 10 0:-30' YEAR TO MINUTE

    -- Produces an error because the negative sign for months must come before the year.
    SELECT INTERVAL '23--2 10 0:30' YEAR TO MINUTE

    -- 0 years, -2 months, 10 days, 0 hours, 30 minutes, and 0 seconds (-0-2 10 0:30:0)
    SELECT INTERVAL '-2 10 0:30' MONTH TO MINUTE

    -- 0 years, 0 months, 0 days, 0 hours, -30 minutes, and -10 seconds (0-0 0 -0:30:10)
    SELECT INTERVAL '-30:10' MINUTE TO SECOND

For more information on how to construct interval with a datetime part range,
see
[Construct an interval with a datetime part range](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#single_datetime_part_interval).

### JSON literals

Syntax:

    JSON 'json_formatted_data'

A JSON literal represents [JSON](https://en.wikipedia.org/wiki/JSON)-formatted data.

Example:

    JSON '
    {
      "id": 10,
      "type": "fruit",
      "name": "apple",
      "on_menu": true,
      "recipes":
        {
          "salads":
          [
            { "id": 2001, "type": "Walnut Apple Salad" },
            { "id": 2002, "type": "Apple Spinach Salad" }
          ],
          "desserts":
          [
            { "id": 3001, "type": "Apple Pie" },
            { "id": 3002, "type": "Apple Scones" },
            { "id": 3003, "type": "Apple Crumble" }
          ]
        }
    }
    '

A JSON literal represents a constant value of the
[JSON data type](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-types#json_type).

## Case sensitivity

GoogleSQL follows these rules for case sensitivity:

| Category | Case-sensitive? | Notes |
|---|---|---|
| Keywords | No |   |
| Built-in Function names | No |   |
| User-Defined Function names | Yes |   |
| Table names | See Notes | Dataset and table names are case-sensitive unless the [`is_case_insensitive`](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/data-definition-language#schema_option_list) option is set to `TRUE`. |
| Column names | No |   |
| Field names | No |   |
| Constant variables | No |   |
| Enum type names | Yes |   |
| String values | Yes | Any value of type `STRING` preserves its case. For example, the result of an expression that produces a `STRING` value or a column value that's of type `STRING`. |
| String comparisons | Yes | However, string comparisons are case-insensitive in [collations](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/collation-concepts) that are case-insensitive. This behavior also applies to operations affected by collation, such as `GROUP BY` and `DISTINCT` clauses. |
| Aliases within a query | No |   |
| Regular expression matching | See Notes | Regular expression matching is case-sensitive by default, unless the expression itself specifies that it should be case-insensitive. |
| `LIKE` matching | Yes |   |
| Module statements | See Notes | In the statement `MODULE x.y.z;`, the identifier path `x.y.z` is case-insensitive. However, some contexts like code linter checks might enforce a specific module name based on the module's source file location. In the statement `IMPORT MODULE x.y.z;`, the identifier path `x.y.z` is case-sensitive in practice because modules are typically loaded from file storage, which treats filenames case-sensitively. |
| Property graph names | No |   |
| Property graph label names | No |   |
| Property graph property names | No |   |

## Reserved keywords

Keywords are a group of tokens that have special meaning in the GoogleSQL
language, and have the following characteristics:

- Keywords can't be used as identifiers unless enclosed by backtick (\`) characters.
- Keywords are case-insensitive.

GoogleSQL has the following reserved keywords.

|---|---|---|---|
| ALL AND ANY ARRAY AS ASC ASSERT_ROWS_MODIFIED AT BETWEEN BY CASE CAST COLLATE CONTAINS CREATE CROSS CUBE CURRENT DEFAULT DEFINE DESC DISTINCT ELSE END | ENUM ESCAPE EXCEPT EXCLUDE EXISTS EXTRACT FALSE FETCH FOLLOWING FOR FROM FULL GRAPH_TABLE GROUP GROUPING GROUPS HASH HAVING IF IGNORE IN INNER INTERSECT INTERVAL INTO | IS JOIN LATERAL LEFT LIKE LIMIT LOOKUP MERGE NATURAL NEW NO NOT NULL NULLS OF ON OR ORDER OUTER OVER PARTITION PRECEDING PROTO QUALIFY RANGE | RECURSIVE RESPECT RIGHT ROLLUP ROWS SELECT SET SOME STRUCT TABLESAMPLE THEN TO TREAT TRUE UNBOUNDED UNION UNNEST USING WHEN WHERE WINDOW WITH WITHIN |

## Terminating semicolons

You can optionally use a terminating semicolon (`;`) when you submit a query
string statement through an Application Programming Interface (API).

In a request containing multiple statements, you must separate statements with
semicolons, but the semicolon is generally optional after the final statement.
Some interactive tools require statements to have a terminating semicolon.

## Trailing commas

You can optionally use a trailing comma (`,`) at the end of a column list in a
`SELECT` statement. You might have a trailing comma as the result of
programmatically creating a column list.

**Example**

    SELECT name, release_date, FROM Books

## Query parameters

You can use query parameters to substitute arbitrary expressions.
However, query parameters can't be used to substitute identifiers,
column names, table names, or other parts of the query itself.
Query parameters are defined outside of the query statement.

Client APIs allow the binding of parameter names to values; the query engine
substitutes a bound value for a parameter at execution time.

Query parameters can't be used in the SQL body of these statements:
`CREATE FUNCTION`, `CREATE VIEW`, `CREATE MATERIALIZED VIEW`, and `CREATE PROCEDURE`.

### Named query parameters

Syntax:

    @parameter_name

A named query parameter is denoted using an [identifier](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#identifiers)
preceded by the `@` character. Named query
parameters can't be used alongside [positional query
parameters](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#positional_query_parameters).

A named query parameter can start with an identifier or a reserved keyword.
An identifier can be unquoted or quoted.

**Example:**

This example returns all rows where `LastName` is equal to the value of the
named query parameter `myparam`.

    SELECT * FROM Roster WHERE LastName = @myparam

### Positional query parameters

Positional query parameters are denoted using the `?` character.
Positional parameters are evaluated by the order in which they are passed in.
Positional query parameters can't be used
alongside [named query parameters](https://docs.cloud.google.com/bigquery/docs/reference/standard-sql/lexical#named_query_parameters).

**Example:**

This query returns all rows where `LastName` and `FirstName` are equal to the
values passed into this query. The order in which these values are passed in
matters. If the last name is passed in first, followed by the first name, the
expected results will not be returned.

    SELECT * FROM Roster WHERE FirstName = ? and LastName = ?

## Comments

Comments are sequences of characters that the parser ignores.
GoogleSQL supports the following types of comments.

### Single-line comments

Use a single-line comment if you want the comment to appear on a line by itself.

**Examples**

    # this is a single-line comment
    SELECT book FROM library;

    -- this is a single-line comment
    SELECT book FROM library;

    /* this is a single-line comment */
    SELECT book FROM library;

    SELECT book FROM library
    /* this is a single-line comment */
    WHERE book = "Ulysses";

### Inline comments

Use an inline comment if you want the comment to appear on the same line as
a statement. A comment that's prepended with `#` or `--` must appear to the
right of a statement.

**Examples**

    SELECT book FROM library; # this is an inline comment

    SELECT book FROM library; -- this is an inline comment

    SELECT book FROM library; /* this is an inline comment */

    SELECT book FROM library /* this is an inline comment */ WHERE book = "Ulysses";

### Multiline comments

Use a multiline comment if you need the comment to span multiple lines.
Nested multiline comments aren't supported.

**Examples**

    SELECT book FROM library
    /*
      This is a multiline comment
      on multiple lines
    */
    WHERE book = "Ulysses";

    SELECT book FROM library
    /* this is a multiline comment
    on two lines */
    WHERE book = "Ulysses";