运算符

算术运算符

运算符	支持的数据类型	说明
+	+(TINYINT) -> TINYINT +(SMALLINT) -> SMALLINT +(INTEGER) -> INTEGER +(BIGINT) -> BIGINT +(FLOAT) -> FLOAT +(DOUBLE) -> DOUBLE +(UTINYINT) -> UTINYINT +(USMALLINT) -> USMALLINT +(UINTEGER) -> UINTEGER +(UBIGINT) -> UBIGINT	一元运算符，表示正数
-	-(TINYINT) -> TINYINT -(SMALLINT) -> SMALLINT -(INTEGER) -> INTEGER -(BIGINT) -> BIGINT -(FLOAT) -> FLOAT -(DOUBLE) -> DOUBLE -(UTINYINT) -> UTINYINT -(USMALLINT) -> USMALLINT -(UINTEGER) -> UINTEGER -(UBIGINT) -> UBIGINT -(INTERVAL) -> INTERVAL	一元运算符，表示负数
+	+(TINYINT, TINYINT) -> TINYINT +(SMALLINT, SMALLINT) -> SMALLINT +(INTEGER, INTEGER) -> INTEGER +(BIGINT, BIGINT) -> BIGINT +(FLOAT, FLOAT) -> FLOAT +(DOUBLE, DOUBLE) -> DOUBLE +(UTINYINT, UTINYINT) -> UTINYINT +(USMALLINT, USMALLINT) -> USMALLINT +(UINTEGER, UINTEGER) -> UINTEGER +(UBIGINT, UBIGINT) -> UBIGINT +(INTERVAL, INTERVAL) -> INTERVAL +(TIMESTAMP, INTERVAL) -> TIMESTAMP +(INTERVAL, TIMESTAMP) -> TIMESTAMP +(TIMESTAMP WITH TIME ZONE, INTERVAL) -> TIMESTAMP WITH TIME ZONE +(INTERVAL, TIMESTAMP WITH TIME ZONE) -> TIMESTAMP WITH TIME ZONE	二元运算符，将两个数值相加。例如，column1 + column2将返回column1和column2相加的结果
-	-(TINYINT, TINYINT) -> TINYINT -(SMALLINT, SMALLINT) -> SMALLINT -(INTEGER, INTEGER) -> INTEGER -(BIGINT, BIGINT) -> BIGINT -(FLOAT, FLOAT) -> FLOAT -(DOUBLE, DOUBLE) -> DOUBLE -(UTINYINT, UTINYINT) -> UTINYINT -(USMALLINT, USMALLINT) -> USMALLINT -(UINTEGER, UINTEGER) -> UINTEGER -(UBIGINT, UBIGINT) -> UBIGINT -(TIMESTAMP, TIMESTAMP) -> INTERVAL -(INTERVAL, INTERVAL) -> INTERVAL -(TIMESTAMP, INTERVAL) -> TIMESTAMP -(TIMESTAMP WITH TIME ZONE, INTERVAL) -> TIMESTAMP WITH TIME ZONE -(TIMESTAMP WITH TIME ZONE, TIMESTAMP WITH TIME ZONE) -> INTERVAL	二元运算符，从一个数值中减去另一个数值。例如，column1 - column2将返回column1减去column2的结果
*	*(TINYINT, TINYINT) -> TINYINT *(SMALLINT, SMALLINT) -> SMALLINT *(INTEGER, INTEGER) -> INTEGER *(BIGINT, BIGINT) -> BIGINT *(FLOAT, FLOAT) -> FLOAT *(DOUBLE, DOUBLE) -> DOUBLE *(UTINYINT, UTINYINT) -> UTINYINT *(USMALLINT, USMALLINT) -> USMALLINT *(UINTEGER, UINTEGER) -> UINTEGER *(UBIGINT, UBIGINT) -> UBIGINT *(INTERVAL, BIGINT) -> INTERVAL *(BIGINT, INTERVAL) -> INTERVAL	二元运算符，将两个数值相乘。例如，column1 * column2将返回column1和column2相乘的结果
/	/(FLOAT, FLOAT) -> FLOAT /(DOUBLE, DOUBLE) -> DOUBLE /(INTERVAL, BIGINT) -> INTERVAL	二元运算符，将一个数值除以另一个数值。例如，column1 / column2将返回column1除以column2的结果

TIP

当不同的数据类型做算术运算并且两种类型直接可以转换时，会发生隐式强制转换。例如: -(INTEGER, DOUBLE) -> -(DOUBLE, DOUBLE) -> DOUBLE

比较运算符

比较算符	支持的数据类型	说明
=	EVERY	用于检查两个值是否相等。示例：WHERE column = value
<> 或 !=	EVERY	用于检查两个值是否不相等。示例：WHERE column <> value或WHERE column != value
>	EVERY	用于检查一个值是否大于另一个值。示例：WHERE column > value
<	EVERY	用于检查一个值是否小于另一个值。示例：WHERE column < value
>=	EVERY	用于检查一个值是否大于或等于另一个值。示例：WHERE column >= value
<=	EVERY	用于检查一个值是否小于或等于另一个值。示例：WHERE column <= value
IS NULL / ISNULL	EVERY	用于检查表达式是否为NULL，如果是则返回true，否则返回false。示例：WHERE column IS NULL
IS NOT NULL / NOTNULL	EVERY	用于检查表达式是否为NULL，如果是则返回false，否则返回true。示例：WHERE column IS NOT NULL

TIP

我们支持的数据类型目前都支持比较运算。当两种不同类型的数据进行比较时，如果可以进行转换则进行隐式强制转换后比较。例如: =(INTEGER, DOUBLE) -> =(DOUBLE, DOUBLE) -> BOOLEAN

逻辑运算符

逻辑运算符	说明
AND	AND运算符要求所有条件都为真时才返回真。如果一个或多个条件为假，则整个表达式为假。示例：WHERE condition1 AND condition2
OR	OR运算符要求至少一个条件为真时就返回真。只有所有条件都为假时才返回假。示例：WHERE condition1 OR condition2
NOT	NOT运算符用于取反条件的值，如果条件为真，则返回假；如果条件为假，则返回真。示例：WHERE NOT condition

TIP

涉及NULL的逻辑操作符并不总是求值为NULL。例如，NULL和false的计算结果为false, NULL或true的计算结果为true。下面是完整的真值表:

a	b	a AND b	a OR b	NOT a
true	true	true	true	false
true	false	false	true	false
true	NULL	NULL	true	false
false	false	false	false	true
false	NULL	false	NULL	true
NULL	NULL	NULL	NULL	NULL