Literals and Syntax

Identifiers

identifier must begin with a letter or _ and may not exceed 128 characters. In addition, all ASCII characters are converted to uppercase.

syntax

[A-Za-z_][A-Za-z0-9_]

Examples

-- identifier start with letter
SELECT 1 as COL1 FROM t1;
-- identifier start with _
SELECT 1 as _COL1 FROM t1;
-- identifier start with _
SELECT 1 as _1 FROM t1;

Literals

Null Literals

The null literal is used to represent the value null for any type. A null literal is compatible with any type.

Typed nulls can be created by a cast over a null literal. For more information, see CAST

Examples:

-- SELECT NULL value from t1
SELECT NULL FROM t1;

-- CAST COL1 AS NULL
SELECT CAST(NULL as INT) as NULL_INT from t1;

Bool Literals

Boolean literals are represented by the keywords true and false.

Examples:

-- true flag
SELECT TRUE from t1;

-- false flag
SELECT FALSE from t1;

Number Literals

Integer literals can be of type Int32 or Int64. An Int32 literal is a series of numeric characters. An Int64 literal is series of numeric characters followed by an uppercase L.

Examples:

-- interger
SELECT 123 from t1;

-- big int
SELECT 1234567890987654321L from t1;

-- float/double
SELECT 3.1415926 from t1;

String Literals

A string is a sequence of bytes or characters, enclosed within either single quote (') or double quote (") characters.

Examples:

-- string with double quote
SELECT "hello" from t1;

-- string with single quote
SELECT 'hello' from t1;

-- empty string with double quote
SELECT "" from t1;

-- empty string with single qoute
SELECT '' from t1;

Timestamp Literals (Planning)

TIMESTAMP 'YYYY-MM-DD HH:MM:SS.DDDDDDD [timezone]]'

Examples:

-- timestamp 
SELECT TIMESTAMP'2020-10-1 12:13:14';

-- timestamp with timezone
SELECT TIMESTAMP'2020-10-1 12:13:14 Asia/Shanghai';

DateTime Literals (Planning)

DATETIME'YYYY-MM-DD HH:MM:SS'

Examples:

-- datetime 
SELECT DATETIME'2020-10-1 12:13:14';

Date Literals (Planning)

A date must have the format: YYYY-MM-DD, where YYYY is a four digit year value between 0001 and 9999, MM is the month between 1 and 12 and DD is the day value that is valid for the given month MM.

-- date 
SELECT DATE'2006-10-1';

Decimal (Planning)

Case sensitivity

Category	Case Sensitive?	Notes
Keywords	No
Function names	No
Table names	No
Column names	No
All type names except for protocol buffer type names	No
String values	Yes	Includes enum value strings
String comparisons	Yes
LIKE matching	Yes

Reserved keywords

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

• Keywords cannot be used as identifiers unless enclosed by backtick (`) characters.

• Keywords are case insensitive.

A~D	E ~ I	J ~ P	R ~ W
ALL AND ANY AS ASC BETWEEN BY CASE CAST CREATE CURRENT DEFAULT DESC DISTINCT	ELSE END EXCLUDE EXISTS FALSE FOLLOWING FOR FROM FULL GROUP GROUPS HASH HAVING IF IGNORE IN INNER INTERSECT INTERVAL INTO IS	JOIN LAST LAST LEFT LIKE LIMIT MERGE NEW NO NOT NULL NULLS OF ON OR ORDER OUTER OVER PARTITION PRECEDING PROTO	RANGE RECURSIVE RESPECT RIGHT ROLLUP ROWS ROWS_RANGE SELECT SET SOME STRUCT TABLESAMPLE THEN TO TREAT TRUE UNBOUNDED UNION USING WHEN WHERE WINDOW WITH WITHIN

Comments

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