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📜  SQL运算子

📅  最后修改于: 2020-11-11 01:28:30             🧑  作者: Mango

SQL运算符

SQL语句通常包含一些保留字或字符，用于执行比较和算术运算等操作。这些保留字或字符称为运算符。

通常，SQL中有三种类型的运算符：

  • SQL算术运算符
  • SQL比较运算符
  • SQL逻辑运算符

SQL算术运算符：

假设两个变量“ a”和“ b”。在此，“ a”的值为50，“ b”的值为100。

例：

Operators Descriptions Examples
+ It is used to add containing values of both operands a+b will give 150
– It subtracts right hand operand from left hand operand a-b will give -50
* It multiply both operand’s values a*b will give 5000
/ It divides left hand operand by right hand operand b/a will give 2
% It divides left hand operand by right hand operand and returns reminder b%a will give 0

SQL比较运算符：

让我们采用两个分别为50和100的变量“ a”和“ b”。

Operator Description Example
= Examine both operands value that are equal or not,if yes condition become true. (a=b) is not true
!= This is used to check the value of both operands equal or not,if not condition become true. (a!=b) is true
< > Examines the operand’s value equal or not, if values are not equal condition is true (a<>b) is true
> Examine the left operand value is greater than right Operand, if yes condition becomes true (a>b) is not true
< Examines the left operand value is less than right Operand, if yes condition becomes true (a
>= Examines that the value of left operand is greater than or equal to the value of right operand or not,if yes condition become true (a>=b) is not true
<= Examines that the value of left operand is less than or equal to the value of right operand or not, if yes condition becomes true (a<=b) is true
!< Examines that the left operand value is not less than the right operand value (a!
!> Examines that the value of left operand is not greater than the value of right operand (a!>b) is true

SQL逻辑运算符：

这是SQL中使用的逻辑运算符的列表。

Operator Description
ALL this is used to compare a value to all values in another value set.
AND this operator allows the existence of multiple conditions in an SQL statement.
ANY this operator is used to compare the value in list according to the condition.
BETWEEN this operator is used to search for values, that are within a set of values
IN this operator is used to compare a value to that specified list value
NOT the NOT operator reverse the meaning of any logical operator
OR this operator is used to combine multiple conditions in SQL statements
EXISTS the EXISTS operator is used to search for the presence of a row in a specified table
LIKE this operator is used to compare a value to similar values using wildcard operator