spark-instrumented-optimizer/docs/sql-ref-literals.md

---
layout: global
title: Literals
displayTitle: Literals
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  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
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---

A literal (also known as a constant) represents a fixed data value. Spark SQL supports the following literals:

 * [String Literal](#string-literal)
 * [Binary Literal](#binary-literal)
 * [Null Literal](#null-literal)
 * [Boolean Literal](#boolean-literal)
 * [Numeric Literal](#numeric-literal)
 * [Datetime Literal](#datetime-literal)
 * [Interval Literal](#interval-literal)

### String Literal

A string literal is used to specify a character string value.

#### Syntax

```sql
'char [ ... ]' | "char [ ... ]"
```

#### Parameters

* **char**

    One character from the character set. Use `\` to escape special characters (e.g., `'` or `\`).
    To represent unicode characters, use 16-bit or 32-bit unicode escape of the form `\uxxxx` or `\Uxxxxxxxx`,
    where xxxx and xxxxxxxx are 16-bit and 32-bit code points in hexadecimal respectively (e.g., `\u3042` for `あ` and `\U0001F44D` for `👍`).

#### Examples

```sql
SELECT 'Hello, World!' AS col;
+-------------+
|          col|
+-------------+
|Hello, World!|
+-------------+

SELECT "SPARK SQL" AS col;
+---------+
|      col|
+---------+
|Spark SQL|
+---------+

SELECT 'it\'s $10.' AS col;
+---------+
|      col|
+---------+
|It's $10.|
+---------+
```

### Binary Literal

A binary literal is used to specify a byte sequence value.

#### Syntax

```sql
X { 'num [ ... ]' | "num [ ... ]" }
```

#### Parameters

* **num**

    Any hexadecimal number from 0 to F.

#### Examples

```sql
SELECT X'123456' AS col;
+----------+
|       col|
+----------+
|[12 34 56]|
+----------+
```

### Null Literal

A null literal is used to specify a null value.

#### Syntax

```sql
NULL
```

#### Examples

```sql
SELECT NULL AS col;
+----+
| col|
+----+
|NULL|
+----+
```

### Boolean Literal

A boolean literal is used to specify a boolean value.

#### Syntax

```sql
TRUE | FALSE
```

#### Examples

```sql
SELECT TRUE AS col;
+----+
| col|
+----+
|true|
+----+
```

### Numeric Literal

A numeric literal is used to specify a fixed or floating-point number.
There are two kinds of numeric literals: integral literal and fractional literal.

#### Integral Literal Syntax

```sql
[ + | - ] digit [ ... ] [ L | S | Y ]
```

#### Integral Literal Parameters

* **digit**

    Any numeral from 0 to 9.

* **L**

    Case insensitive, indicates `BIGINT`, which is an 8-byte signed integer number.

* **S**

    Case insensitive, indicates `SMALLINT`, which is a 2-byte signed integer number.

* **Y**

    Case insensitive, indicates `TINYINT`, which is a 1-byte signed integer number.

* **default (no postfix)**

    Indicates a 4-byte signed integer number.

#### Integral Literal Examples

```sql
SELECT -2147483648 AS col;
+-----------+
|        col|
+-----------+
|-2147483648|
+-----------+

SELECT 9223372036854775807l AS col;
+-------------------+
|                col|
+-------------------+
|9223372036854775807|
+-------------------+

SELECT -32Y AS col;
+---+
|col|
+---+
|-32|
+---+

SELECT 482S AS col;
+---+
|col|
+---+
|482|
+---+
```

#### Fractional Literals Syntax

decimal literals:
```sql
decimal_digits { [ BD ] | [ exponent BD ] } | digit [ ... ] [ exponent ] BD
```

double literals:
```sql
decimal_digits  { D | exponent [ D ] }  | digit [ ... ] { exponent [ D ] | [ exponent ] D }
```

float literals:
```sql
decimal_digits  { F | exponent [ F ] }  | digit [ ... ] { exponent [ F ] | [ exponent ] F }
```

While decimal_digits is defined as
```sql
[ + | - ] { digit [ ... ] . [ digit [ ... ] ] | . digit [ ... ] }
```

and exponent is defined as
```sql
E [ + | - ] digit [ ... ]
```

#### Fractional Literals Parameters

* **digit**

    Any numeral from 0 to 9.

* **D**

    Case insensitive, indicates `DOUBLE`, which is an 8-byte double-precision floating point number.

* **F**

    Case insensitive, indicates `FLOAT`, which is a 4-byte single-precision floating point number.

* **BD**

    Case insensitive, indicates `DECIMAL`, with the total number of digits as precision and the number of digits to right of decimal point as scale.

#### Fractional Literals Examples

```sql
SELECT 12.578 AS col;
+------+
|   col|
+------+
|12.578|
+------+

SELECT -0.1234567 AS col;
+----------+
|       col|
+----------+
|-0.1234567|
+----------+

SELECT -.1234567 AS col;
+----------+
|       col|
+----------+
|-0.1234567|
+----------+

SELECT 123. AS col;
+---+
|col|
+---+
|123|
+---+

SELECT 123.BD AS col;
+---+
|col|
+---+
|123|
+---+

SELECT 5E2 AS col;
+-----+
|  col|
+-----+
|500.0|
+-----+

SELECT 5D AS col;
+---+
|col|
+---+
|5.0|
+---+

SELECT -5BD AS col;
+---+
|col|
+---+
| -5|
+---+

SELECT 12.578e-2d AS col;
+-------+
|    col|
+-------+
|0.12578|
+-------+

SELECT -.1234567E+2BD AS col;
+---------+
|      col|
+---------+
|-12.34567|
+---------+

SELECT +3.e+3 AS col;
+------+
|   col|
+------+
|3000.0|
+------+

SELECT -3.E-3D AS col;
+------+
|   col|
+------+
|-0.003|
+------+
```

### Datetime Literal

A datetime literal is used to specify a date or timestamp value.

#### Date Syntax

```sql
DATE { 'yyyy' |
       'yyyy-[m]m' |
       'yyyy-[m]m-[d]d' |
       'yyyy-[m]m-[d]d[T]' }
```
**Note:** defaults to `01` if month or day is not specified.

#### Date Examples

```sql
SELECT DATE '1997' AS col;
+----------+
|       col|
+----------+
|1997-01-01|
+----------+

SELECT DATE '1997-01' AS col;
+----------+
|       col|
+----------+
|1997-01-01|
+----------+

SELECT DATE '2011-11-11' AS col;
+----------+
|       col|
+----------+
|2011-11-11|
+----------+
```

#### Timestamp Syntax

```sql
TIMESTAMP { 'yyyy' |
            'yyyy-[m]m' |
            'yyyy-[m]m-[d]d' |
            'yyyy-[m]m-[d]d ' |
            'yyyy-[m]m-[d]d[T][h]h[:]' |
            'yyyy-[m]m-[d]d[T][h]h:[m]m[:]' |
            'yyyy-[m]m-[d]d[T][h]h:[m]m:[s]s[.]' |
            'yyyy-[m]m-[d]d[T][h]h:[m]m:[s]s.[ms][ms][ms][us][us][us][zone_id]'}
```
**Note:** defaults to `00` if hour, minute or second is not specified.
`zone_id` should have one of the forms:
* Z - Zulu time zone UTC+0
* `+|-[h]h:[m]m`
* An id with one of the prefixes UTC+, UTC-, GMT+, GMT-, UT+ or UT-, and a suffix in the formats:
  * `+|-h[h]`
  * `+|-hh[:]mm`
  * `+|-hh:mm:ss`
  * `+|-hhmmss`
* Region-based zone IDs in the form `area/city`, such as `Europe/Paris`

**Note:** defaults to the session local timezone (set via `spark.sql.session.timeZone`) if `zone_id` is not specified.

#### Timestamp Examples

```sql
SELECT TIMESTAMP '1997-01-31 09:26:56.123' AS col;
+-----------------------+
|                    col|
+-----------------------+
|1997-01-31 09:26:56.123|
+-----------------------+

SELECT TIMESTAMP '1997-01-31 09:26:56.66666666UTC+08:00' AS col;
+--------------------------+
|                      col |
+--------------------------+
|1997-01-30 17:26:56.666666|
+--------------------------+

SELECT TIMESTAMP '1997-01' AS col;
+-------------------+
|                col|
+-------------------+
|1997-01-01 00:00:00|
+-------------------+
```

### Interval Literal

An interval literal is used to specify a fixed period of time.
The interval literal supports two syntaxes: ANSI syntax and multi-units syntax.

#### ANSI Syntax

The ANSI SQL standard defines interval literals in the form:
```sql
INTERVAL [ <sign> ] <interval string> <interval qualifier>
```
where `<interval qualifier>` can be a single field or in the field-to-field form:
```sql
<interval qualifier> ::= <start field> TO <end field> | <single field>
```
The field name is case-insensitive, and can be one of `YEAR`, `MONTH`, `DAY`, `HOUR`, `MINUTE` and `SECOND`.

An interval literal can have either year-month or day-time interval type. The interval sub-type defines format of `<interval string>`:
```sql
<interval string> ::= <quote> [ <sign> ] { <year-month literal> | <day-time literal> } <quote>
<year-month literal> ::= <years value> [ <minus sign> <months value> ] | <months value>
<day-time literal> ::= <day-time interval> | <time interval>
<day-time interval> ::= <days value> [ <space> <hours value> [ <colon> <minutes value> [ <colon> <seconds value> ] ] ]
<time interval> ::= <hours value> [ <colon> <minutes value> [ <colon> <seconds value> ] ]
  | <minutes value> [ <colon> <seconds value> ]
  | <seconds value>
```

Supported year-month interval literals and theirs formats:

|`<interval qualifier>`|Interval string pattern|An instance of the literal|
|---------|-------|------------|
|YEAR|`[+|-]'[+|-]y'`|`INTERVAL -'2021' YEAR`|
|YEAR TO MONTH|`[+|-]'[+|-]y-m'`|`INTERVAL '-2021-07' YEAR TO MONTH`|
|MONTH|`[+|-]'[+|-]m'`|`interval '10' month`|

Formats of supported day-time interval literals:

|`<interval qualifier>`|Interval string pattern|An instance of the literal|
|---------|----|-------------------|
|DAY|`[+|-]'[+|-]d'`|`INTERVAL -'100' DAY`|
|DAY TO HOUR|`[+|-]'[+|-]d h'`|`INTERVAL '-100 10' DAY TO HOUR`|
|DAY TO MINUTE|`[+|-]'[+|-]d h:m'`|`INTERVAL '100 10:30' DAY TO MINUTE`|
|DAY TO SECOND|`[+|-]'[+|-]d h:m:s.n'`|`INTERVAL '100 10:30:40.999999' DAY TO SECOND`|
|HOUR|`[+|-]'[+|-]h'`|`INTERVAL '123' HOUR`|
|HOUR TO MINUTE|`[+|-]'[+|-]h:m'`|`INTERVAL -'-123:10' HOUR TO MINUTE`|
|HOUR TO SECOND|`[+|-]'[+|-]h:m:s.n'`|`INTERVAL '123:10:59' HOUR TO SECOND`|
|MINUTE|`[+|-]'[+|-]m'`|`interval '1000' minute`|
|MINUTE TO SECOND|`[+|-]'[+|-]m:s.n'`|`INTERVAL '1000:01.001' MINUTE TO SECOND`|
|SECOND|`[+|-]'[+|-]s.n'`|`INTERVAL '1000.000001' SECOND`|

#### ANSI Examples

```sql
SELECT INTERVAL '2-3' YEAR TO MONTH AS col;
+----------------------------+
|col                         |
+----------------------------+
|INTERVAL '2-3' YEAR TO MONTH|
+----------------------------+

SELECT INTERVAL -'20 15:40:32.99899999' DAY TO SECOND AS col;
+--------------------------------------------+
|col                                         |
+--------------------------------------------+
|INTERVAL '-20 15:40:32.998999' DAY TO SECOND|
+--------------------------------------------+
```

#### Multi-units Syntax

```sql
INTERVAL interval_value interval_unit [ interval_value interval_unit ... ] |
INTERVAL 'interval_value interval_unit [ interval_value interval_unit ... ]' |
```

#### Multi-units Parameters

* **interval_value**

    **Syntax:**

      [ + | - ] number_value | '[ + | - ] number_value'

* **interval_unit**

    **Syntax:**

      YEAR[S] | MONTH[S] | WEEK[S] | DAY[S] | HOUR[S] | MINUTE[S] | SECOND[S] |
      MILLISECOND[S] | MICROSECOND[S]

      Mix of the YEAR[S] or MONTH[S] interval units with other units is not allowed.

#### Multi-units Examples

```sql
SELECT INTERVAL 3 YEAR AS col;
+-------+
|    col|
+-------+
|3 years|
+-------+

SELECT INTERVAL -2 HOUR '3' MINUTE AS col;
+--------------------+
|                 col|
+--------------------+
|-1 hours -57 minutes|
+--------------------+

SELECT INTERVAL '1 YEAR 2 DAYS 3 HOURS';
+----------------------+
|                   col|
+----------------------+
|1 years 2 days 3 hours|
+----------------------+

SELECT INTERVAL 1 YEARS 2 MONTH 3 WEEK 4 DAYS 5 HOUR 6 MINUTES 7 SECOND 8
    MILLISECOND 9 MICROSECONDS AS col;
+-----------------------------------------------------------+
|                                                        col|
+-----------------------------------------------------------+
|1 years 2 months 25 days 5 hours 6 minutes 7.008009 seconds|
+-----------------------------------------------------------+
```