存储过程可选参数的默认值分配

Question

我有一个存储过程的参数，我希望从表中指定默认值，我该怎么做？

ALTER PROCEDURE [DBO].[Test] 

     @planId int = 1 (This I can do) 

但我想这样做

@planId int = (Select Id from Table1 Where name = ‘ABC’) ‘ Assign default id from a table 

Answer 1

如果你想这样做，只是分配0开始，并在程序的第一行这个值写入该变量。

ALTER PROCEDURE [DBO].[Test] 
@planId int = 0 
AS 
BEGIN 
SET @planId = (Select Id from Table1 Where name = ‘ABC’) 
... 
... 
... 
END 

Answer 2

在存储过程中，您可以声明和设置值。在这种情况下，您可以设置@planId，无论你在体内要则：

CREATE PROCEDURE procedureName 
    @planId int = null output 
AS 
    IF @planId = null 
     Begin 
     SET @planId = (Select Id from Table1 Where name = ‘ABC’) 
     End 
    ELSE --> then they gave you the value