如何在 SQL 服务器存储过程中使用 if/else

Question

我有以下存储过程：

ALTER PROCEDURE [dbo].[Provider]
(@strPro varchar(200))
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT * 
    FROM [db1].[dbo].[table1]
    WHERE [Name] = @strPro
END

我有一个下拉列表，其中包含以下条目：

All People
John D.
Mike K.
Alan H.
Paul Q.

如何修改存储过程，以便如果用户选择 All People，WHERE 语句将是 LIKE 而不是 = 符号

示例：

ALTER PROCEDURE [dbo].[Provider]
(@strPro varchar(200))
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT * 
    FROM [db1].[dbo].[table1]

    if @strPro = 'All People'
    BEGIN
        WHERE [Name] LIKE '%'
    END
    ELSE
    BEGIN
        WHERE [Name] = @strPro
    END
END

Answer 1

像这样

SELECT * FROM [db1].[dbo].[table1]
WHERE @strPro = 'All People' OR [Name] = @strPro

如果 "All People" 被传递 - 第一个条件将为真并且所有记录将被返回（你不需要做 LIKE '%'）否则只有匹配 [Name] 的记录将被返回.

Answer 2

尝试这样的事情，在存储过程中构建 SQL 语句：

ALTER PROCEDURE [dbo].[Provider]
(
    @strPro varchar(200)
)

AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    DECLARE @SQL varchar(2000)

    -- Insert statements for procedure here
    SET @SQL = 'SELECT * FROM [db1].[dbo].[table1] '

    if @strPro <> 'All People'
    BEGIN
        SET @SQL = @SQL + ' WHERE [Name] = ''' + @strPro + '''
    END

    EXEC (@SQL)

END

注意 1：如果您想要 'All People' ...，则不需要 WHERE 子句注意2：您可能需要调整一些单引号...

如何在 SQL 服务器存储过程中使用 if/else

How to use if/else in SQL Server stored procedure

sql

sql-server

stored-procedures