运算符

运算符优先级

%left "OR"
%left "AND"
%left "XOR"
%left UNARY_NOT_PRECEDENCE // (NOT / !)
%nonassoc "=" "==" "<>" ">" "<" ">=" "<=" "!=" "LIKE" "ILIKE" "RLIKE" "IN" "DISTINCT" "BETWEEN" "IS" "NOT_SPECIAL"
%nonassoc "ESCAPE"
%left "|"
%left "^"
%left "&"
%left "<<" ">>"
%left "+" "-"
%left "||"
%left "*" "/" "DIV" "%" "MOD"
%left UNARY_PRECEDENCE  // For all unary operators, +, -, ~

各类运算

1. 比较运算

操作符名	功能描述
>	大于
>=	大于等于
<	小于
<=	小于等于
!= , <>	不等于
=, ==	等于
BEWTEEN...AND	介于…和…之间
IN	在…集合中
LIKE	模糊匹配，大小写敏感
ILIKE	模糊匹配, 大小写不敏感
RLIKE	正则表达式匹配

2. 逻辑运算

操作符名	功能描述
AND	逻辑与
OR	逻辑或
XOR	逻辑与或
NOT, !	逻辑非, unary operator

3. 算术运算

操作符名	功能描述
%, MOD	Modulo
*	Multiplication
+	Addition
-	Subtraction
/	Float division
DIV	Integer division
+	Unary plus
-	Unary minus, 只支持数值型操作数-number

4. 位运算

操作符名	Description
&	Bitwise AND
|	Bitwise OR
^	Bitwise XOR
~	Bitwise NOT, unary operator

5. 类型运算和函数

操作符名	Description
CAST	CAST expr AS dist_type，将表达式expr强转为目标类型
bool	bool(expr)，将表达式转换BOOL类型
smallint	smallint(expr)，将表达式转换SMALLINT类型
int	int(expr)，将表达式转换INT类型
bigint	bigint(expr)，将表达式转换为BIGINT类型
string(expr)	string(expr)，将表达式转换为STRING类型

类型间转换兼容情况

Safe: 表示从从原类型转换为目标类型的转换是安全的，不会丢失精度也不会计算异常。例如，从int转成bigint不安全的：

SELECT BIGINT(12345);
-- 12345

Unsafe: 表示从原类型转换为目标类型的转换不安全的，数据转换后可能丢失精度或者发生异常。

SELECT INT(1.2);
-- output 1

X：表示从原类型转换为目标类型的转换是不支持的

src|dist	bool	smallint	int	float	int64	double	timestamp	date	string
bool	Safe	Safe	Safe	Safe	Safe	Safe	UnSafe	X	Safe
smallint	UnSafe	Safe	Safe	Safe	Safe	Safe	UnSafe	X	Safe
int	UnSafe	UnSafe	Safe	Safe	Safe	Safe	UnSafe	X	Safe
float	UnSafe	UnSafe	UnSafe	Safe	Safe	Safe	UnSafe	X	Safe
bigint	UnSafe	UnSafe	UnSafe	UnSafe	Safe	UnSafe	UnSafe	X	Safe
double	UnSafe	UnSafe	UnSafe	UnSafe	UnSafe	Safe	UnSafe	X	Safe
timestamp	UnSafe	UnSafe	UnSafe	UnSafe	Safe	UnSafe	Safe	UnSafe	Safe
date	UnSafe	X	X	X	X	X	UnSafe	Safe	Safe
string	UnSafe	UnSafe	UnSafe	UnSafe	UnSafe	UnSafe	UnSafe	UnSafe	Safe

赋值操作符

操作符名	功能描述
=	赋值 (可用于 SET 语句中 )