SQL复制 -- Create a variable with a default>DECLAREVARIABLEmyvarINTDEFAULT5; >VALUES(myvar); 5-- Setting a variable>SETVARmyvar = (SELECTsum(c1)FROMVALUES(1), (2)AST(c1); >VALUES(myvar); 3-- Variables are the ou
Consider one example where we will declare one variable named @wishes that won’t have any initial value and will have a varchar data type. We will assign the value string ‘Hey! Good Morning My Friend! Learn SQL on EDUCBA with payal.’ to the @wishes variable using the SET statement in...
声明复合语句 (BEGIN... END) 中的SQL 变量。 快速链接: 转至参数 转至示例 转至用法 转至标准 转至权限 语法 DECLARE <variable_name> [ , … ] <data-type> [{ = | DEFAULT} initial-value] initial-value - (back to Syntax) special-value | <string> | [ - ] <number> | ( <constant-...
U-SQL نسخ DECLARE @value string = "overwritten declaration"; DECLARE EXTERNAL @value string = "external declaration"; @r = SELECT * FROM (VALUES(@value)) AS T(x); OUTPUT @r TO "/output/test.csv" USING Outputters.Csv(); Differences from T-SQL Unlike T-SQL, a variable ...
IFmy_variable>10THENSELECTCONCAT('Value is: ',my_variable);-- 如果变量大于10,输出变量值ELSESELECT'Value is less than or equal to 10';-- 否则,输出另一条消息ENDIF; 1. 2. 3. 4. 5. 解释: IF my_variable > 10 THEN ... END IF;:根据my_variable的值执行不同的 SQL 语句,进行条件判断...
To test this, attempt to change the variable's value to a string of characters. declare testvar="example"Copy Usethe echo commandto see the value of the variable. echo $testvarCopy The output shows the value of zero (0): The value of a variable can also be the result of a mathemati...
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Use the DECLARE statement to define a variable, the data type of the variable and, optionally, its initial value. You can define three types of variable with the DECLARE statement: External Normal Shared For more information, seeESQL variables. ...
1. 声明变量: 在 SQL 中,我们可以使用 declare 关键字来声明一个变量。声明变量 的语法如下: ``` DECLARE @variable_name data_type [= initial_value]; ``` 其中,@variable_name 是变量的名称,data_type 是变量的数据类 型,initial_value 是可选项,用于为变量指定初始值。 下面是一些常见的数据类型: -...
Use the DECLARE statement to define a variable, the data type of the variable and, optionally, its initial value. You can define three types of variable with the DECLARE statement: External Normal Shared For further information, seeESQL variables. ...