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huaxingao committed Apr 19, 2020
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218 changes: 169 additions & 49 deletions docs/sql-ref-literals.md
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Expand Up @@ -32,12 +32,20 @@ A literal (also known as a constant) represents a fixed data value. Spark SQL su

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

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
'...' | "..."
'c [ ... ]' | "c [ ... ]"
{% endhighlight %}
...: indicates any string.

#### <em>Parameters</em>

<dl>
<dt><code><em>c</em></code></dt>
<dd>
One character from the character set. Use <code>\</code> to escape special characters.
</dd>
</dl>

#### <em>Examples</em>

Expand All @@ -61,20 +69,20 @@ SELECT SELECT 'it\'s $10.' AS col;
| col|
+---------+
|It's $10.|
+----------+
+---------+
{% endhighlight %}

### Null Literal

A null literal is used to specify a null value.

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
NULL
{% endhighlight %}

#### <em>Examples</em>
#### Examples

{% highlight sql %}
SELECT NULL AS col;
Expand All @@ -89,13 +97,13 @@ SELECT NULL AS col;

A boolean literal is used to specify a boolean value.

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
TRUE | FALSE
{% endhighlight %}

#### <em>Examples</em>
#### Examples

{% highlight sql %}
SELECT TRUE AS col;
Expand All @@ -112,17 +120,45 @@ A numeric literal is used to specify a fixed or floating-point number.

#### Integer Literal

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
[ + | - ] digit [ ... ] [ L | S | Y ]
{% endhighlight %}
digit: one of 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9. <br>
default (no postfix): indicates a 4-byte signed integer number.<br>
L: case insensitive, indicates <code>BIGINT</code>, which is a 8-byte signed integer number.<br>
S: case insensitive, indicates <code>SMALLINT</code>, which is a 2-byte signed integer number.<br>
Y: case insensitive, indicates <code>TINYINT</code>, which is a 1-byte signed integer number.<br>
#### <em>Examples</em>

#### Parameters

<dl>
<dt><code><em>digit</em></code></dt>
<dd>
Any numeral from 0 to 9.
</dd>
</dl>
<dl>
<dt><code><em>L</em></code></dt>
<dd>
Case insensitive, indicates <code>BIGINT</code>, which is a 8-byte signed integer number.
</dd>
</dl>
<dl>
<dt><code><em>S</em></code></dt>
<dd>
Case insensitive, indicates <code>SMALLINT</code>, which is a 2-byte signed integer number.
</dd>
</dl>
<dl>
<dt><code><em>Y</em></code></dt>
<dd>
Case insensitive, indicates <code>TINYINT</code>, which is a 1-byte signed integer number.
</dd>
</dl>
<dl>
<dt><code><em>default (no postfix)</em></code></dt>
<dd>
Indicates a 4-byte signed integer number.
</dd>
</dl>
#### Examples

{% highlight sql %}
SELECT -2147483648 AS col;
Expand Down Expand Up @@ -156,13 +192,22 @@ SELECT 482S AS col;

#### Decimal Literal

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
[ + | - ] { digit [ ... ] . [ digit [ ... ] ] | . digit [ ... ] }
{% endhighlight %}

#### <em>Examples</em>
#### Parameters

<dl>
<dt><code><em>digit</em></code></dt>
<dd>
Any numeral from 0 to 9.
</dd>
</dl>

#### Examples

{% highlight sql %}
SELECT 12.578 AS col;
Expand All @@ -189,18 +234,42 @@ SELECT -.1234567 AS col;

#### Floating Point and BigDecimal Literals

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
[ + | - ] { digit [ ... ] [ E [ + | - ] digit [ ... ] ] [ D | BD ]
| digit [ ... ] . [ digit [ ... ] ] [ E [ + | - ] digit [ ... ] ] [ D | BD ]
| . digit [ ... ] [ E [ + | - ] digit [ ... ] ] [ D | BD ] }
[ + | - ] { digit [ ... ] [ E [ + | - ] digit [ ... ] ] [ D | BD ] |
digit [ ... ] . [ digit [ ... ] ] [ E [ + | - ] digit [ ... ] ] [ D | BD ] |
. digit [ ... ] [ E [ + | - ] digit [ ... ] ] [ D | BD ] }
{% endhighlight %}
digit: one of 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9. <br>
default (no postfix): indicate a 4-byte single-precision floating point number.<br>
D: case insensitive, indicates <code>DOUBLE</code>, which is a 8-byte double-precision floating point number.<br>
BD: case insensitive, indicates <code>BIGDECIMAL</code>, which is an arbitrary-precision signed decimal number.<br>
#### <em>Examples</em>

#### Parameters

<dl>
<dt><code><em>digit</em></code></dt>
<dd>
Any numeral from 0 to 9.
</dd>
</dl>
<dl>
<dt><code><em>D</em></code></dt>
<dd>
Case insensitive, indicates <code>DOUBLE</code>, which is a 8-byte double-precision floating point number.
</dd>
</dl>
<dl>
<dt><code><em>BD</em></code></dt>
<dd>
Case insensitive, indicates <code>BIGDECIMAL</code>, which is an arbitrary-precision signed decimal number.
</dd>
</dl>
<dl>
<dt><code><em>default (no postfix)</em></code></dt>
<dd>
Indicate a 4-byte single-precision floating point number.
</dd>
</dl>

#### Examples

{% highlight sql %}
SELECT 5E2 AS col;
Expand All @@ -221,7 +290,7 @@ SELECT -5BD AS col;
+---+
|col|
+---+
|-5 |
| -5|
+---+

SELECT 12.578e-2d AS col;
Expand Down Expand Up @@ -259,13 +328,26 @@ A Datetime literal is used to specify a datetime value.

#### Date Literal

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
DATE 'yyyy [ -MM-dd ]'
DATE { 'yyyy' |
'yyyy-[m]m' |
'yyyy-[m]m-[d]d' |
'yyyy-[m]m-[d]d ' |
'yyyy-[m]m-[d]d[T]c[...]' }
{% endhighlight %}

#### <em>Examples</em>
#### Parameters

<dl>
<dt><code><em>c</em></code></dt>
<dd>
One character from the character set.
</dd>
</dl>

#### Examples

{% highlight sql %}
SELECT DATE '1997' AS col;
Expand All @@ -292,13 +374,40 @@ SELECT DATE '2011-11-11' AS col;

#### Timestamp Literal

#### <em>Syntax</em>
#### Syntax

{% highlight sql %}
TIMESTAMP { 'yyyy [ -MM-dd HH:mm:ss.SSSSSSzzz ]' | '[ yyyy-MM-dd ] HH:mm [ :ss.SSSSSSzzz ]' }
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]' |
'[T][h]h:' |
'[T][h]h:[m]m[:]' |
'[T][h]h:[m]m:[s]s[.]' |
'T[h]h' |
'[T][h]h:[m]m:[s]s.[ms][ms][ms][us][us][us][zone_id]' }
{% endhighlight %}

#### <em>Examples</em>
`zone_id` should have one of the forms:
<ul>
<li>Z - Zulu time zone UTC+0</li>
<li>+|-[h]h:[m]m</li>
<li>A short id, see <a href="https://docs.oracle.com/javase/8/docs/api/java/time/ZoneId.html#SHORT_IDS">SHORT_IDS</a></li>
<li>An id with one of the prefixes UTC+, UTC-, GMT+, GMT-, UT+ or UT-, and a suffix in the formats:
<ul>
<li>+|-h[h]</li>
<li>+|-hh[:]mm</li>
<li>+|-hh:mm:ss</li>
<li>+|-hhmmss</li>
</ul>
</li>
<li>Region-based zone IDs in the form <code>area/city</code>, such as <code>Europe/Paris</code></li>
</ul>

#### Examples

{% highlight sql %}
SELECT TIMESTAMP '1997-01-31 09:26:56.123' AS col;
Expand Down Expand Up @@ -334,24 +443,35 @@ SELECT TIMESTAMP '09:26' AS col;

An interval literal is used to specify a fixed period of time.

#### <em>Syntax</em>
{% highlight sql %}
{ INTERVAL interval_value interval_unit [ interval_value interval_unit ... ]
| INTERVAL interval_value interval_unit TO interval_unit }
{% endhighlight %}

interval_value:
{% highlight sql %}
{ [ + | - ] number_value | string_value }
{% endhighlight %}
Note: string_value needs to be used for INTERNAL ... TO ... format.

interval_unit:
#### Syntax
{% highlight sql %}
YEAR | MONTH | DAY | HOUR | MINUTE | SECOND | MILLISECOND | MICROSECOND
{ INTERVAL interval_value interval_unit [ interval_value interval_unit ... ] |
INTERVAL interval_value interval_unit TO interval_unit }
{% endhighlight %}

#### <em>Examples</em>
#### Parameters

<dl>
<dt><code><em>interval_value</em></code></dt>
<dd>
<b>Syntax:</b>
<code>
{ [ + | - ] number_value | string_value }
</code><br>
Note: string_value needs to be used for <code>INTERNAL</code> ... <code>TO</code> ... format.
</dd>
</dl>
<dl>
<dt><code><em>interval_unit</em></code></dt>
<dd>
<b>Syntax:</b>
<code>
YEAR | MONTH | DAY | HOUR | MINUTE | SECOND | MILLISECOND | MICROSECOND
</code>
</dd>
</dl>

#### Examples

{% highlight sql %}
SELECT INTERVAL 3 YEAR AS col;
Expand Down

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