Sql 如何将常规条件添加到sp select？

我真的不知道在这种情况下该怎么办，所以不要太苛刻

如果我有自己的选择：

declare @Id uniqueidentifier = 'some parent guid'
declare @Type int = 1 -- can be 1, 2 or 3
declare @UserType varchar(max) --can be 0, anything else than 0, or all users at once

if(@Type = 1)
set @UserType = 'and UserType <> 0'
if(@Type = 2)
set @UserType = 'and UserType = 0'
if(@Type = 3)
set @UserType = ''
    select * from users where parentId = @Id + @UserType 

如果条件是通用的，该怎么办？我真的需要创建3个不同的Sp吗

您可以使用AND/OR逻辑来模拟where子句中的If else条件。试试这样的

select * from users 
where
parentid= @id 
and 
(
(@Type = 1 and UserType <> 0)
or 
(@Type = 2 and UserType = 0)
or 
(@Type = 3)
)

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不同的select语句效率最高，因为每个语句都是一个根本不同的查询。如果静态SQL变得笨拙，请使用动态SQL。下面是一个使用中的技术的参数化示例

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不同的select语句效率最高，因为每个语句都是一个根本不同的查询。下面是一个动态SQL示例，使用

declare @Id uniqueidentifier = 'some parent guid'
declare @Type int = 1 -- can be 1, 2 or 3
Declare @UserType varchar(max) --can be 0, anything else than 0, or all users at once
Declare @sql nvarchar(max)

if(@Type = 1)
set @UserType = ' and UserType <> 0'
if(@Type = 2)
set @UserType = ' and UserType = 0'
if(@Type = 3)
set @UserType = ''

set @sql = 'select * from users where parentId ='''+ cast(@Id as varchar(25))+''''+ @UserType 

--Print @sql

Exec sp_executesql @sql

declare @sql nvarchar(MAX) = N'select * from users where parentId = @Id';
declare @Id uniqueidentifier = 'some parent guid';
declare @Type int = 1; -- can be 1, 2 or 3
declare @UserType varchar(max); --can be 0, anything else than 0, or all users at once

SET @sql = @sql + CASE @Type
    WHEN 1 THEN N' and UserType <> 0'
    WHEN 2 THEN N' and UserType = 0'
    WHEN 3 THEN N'' END;

EXEC sp_executesql
      @sql
    , N'@Id uniqueidentifier'
    , @Id = @Id;