sql - 关键字“SELECT”附近的语法不正确

Question

我有以下从视图调用的 SQL 函数

ALTER FUNCTION [dbo].[GetModulesforTesCaseID] 
(@TestCaseID numeric(18))
RETURNS VARCHAR(1000)
AS
BEGIN
declare @Modules VARCHAR(1000)
select @Modules = SUBSTRING(
(SELECT ',' + cast (S.MODULENAME as varchar)
FROM MODULE s JOIN EFFMODFORTESTCASE EMTC ON S.MODULEID = EMTC.MODULEID
JOIN TESTCASE TC ON TC.TESTCASEID =  EMTC.TESTCASEID
where tc.testcaseid = @TestCaseID
ORDER BY s.MODULENAME
FOR XML PATH('')),2,200000)

    if @Modules is null BEGIN
            set @Modules = SELECT M.MODULENAME FROM MODULE M JOIN SUBMODULESFORMODULE SFM ON SFM.MODULEID = M.MODULEID 
            JOIN EFFSUBMODFORTESTCASE ESMTC ON ESMTC.SUBMODULEID = SFM.SUBMODULEID WHERE TESTCASEID = @TestCaseID
    END 

return @Modules
end

我正进入（状态

消息 156，级别 15，状态 1，过程 GetModulesforTesCaseID，第 16 行
关键字“SELECT”附近的语法不正确

请帮助我纠正 If 条件下的语法错误

Answer 1

错误是当您将值分配@Modules给IF. 试试这个（你需要确保结果SELECT只返回一行）：

ALTER FUNCTION [dbo].[GetModulesforTesCaseID] 
(@TestCaseID numeric(18))
RETURNS VARCHAR(1000)
AS
BEGIN
declare @Modules VARCHAR(1000)
select @Modules = SUBSTRING(
(SELECT ',' + cast (S.MODULENAME as varchar)
FROM MODULE s JOIN EFFMODFORTESTCASE EMTC ON S.MODULEID = EMTC.MODULEID
JOIN TESTCASE TC ON TC.TESTCASEID =  EMTC.TESTCASEID
where tc.testcaseid = @TestCaseID
ORDER BY s.MODULENAME
FOR XML PATH('')),2,200000)

    if @Modules is null BEGIN
            SELECT @Modules = M.MODULENAME 
            FROM MODULE M 
            INNER JOIN SUBMODULESFORMODULE SFM 
                ON SFM.MODULEID = M.MODULEID 
            INNER JOIN EFFSUBMODFORTESTCASE ESMTC 
                ON ESMTC.SUBMODULEID = SFM.SUBMODULEID 
            WHERE TESTCASEID = @TestCaseID
    END 

return @Modules
end