Question

CREATE TABLE #MyTasks  
(TaskId   int,  
   CompanyId      int,
   YearCol varchar(50),
   MonthCol varchar(50),
   SomeValue varchar(50)
  );  
GO  

INSERT INTO #MyTasks 
SELECT 220,1,2018,1,50553.32
UNION
SELECT 220,2,2018,2,222038.12

DECLARE @Param1 int = 1
DECLARE @Param2 int = 0
SELECT * FROM #MyTasks
WHERE
(@Param1 != 0 AND taskid in (select taskid from #mytasks where companyid = @param1) OR @Param1 = 0)
OR
(@Param2 != 0 AND taskid in (select taskid from #mytasks where companyid = @param2) OR @Param2 = 0) -- because of this condition, all rows are being returned

如果@ Param1没有传递给存储过程，如何从#MyTasks表返回所有行？我最初将其设置为0，并且仅在通过且与0有所不同时才想使用where子句。

Answer 1

只需在where子句上使用一些括号并添加一个print (model_dict) {'Select Model': ['empty', None], 'Jet Fighter': ['MODEL1_530', 'NOT_AVAILABLE'], 'Jet Fighter2': ['MODEL2_540', 'NOT_AVAILABLE']}条件。

OR

这可以进一步简化为

WHERE
(@Param1 != 0 AND taskid in (select taskid from #mytasks where companyid = @Param1))
or @Param1 = 0 --usually this would be IS NULL

或具有多个参数...

WHERE companyid = @Param1 or @Param1 = 0

Answer 2

如果您在同一张桌子上工作，请不要使用不使用或仅在where子句中使用它，因为它两次都不会读取完整表。

可以通过以下方式完成：

CREATE TABLE #MyTasks  
(TaskId   int,  
   CompanyId      int,
   YearCol varchar(50),
   MonthCol varchar(50),
   SomeValue varchar(50)
  );  
GO  

INSERT INTO #MyTasks 
SELECT 220,1,2018,1,50553.32
UNION
SELECT 220,2,2018,2,222038.12

DECLARE @Param1 int = 0
SELECT * FROM #MyTasks
WHERE @param1 = 0 or companyid = @param1

带IN运算符的条件where子句不起作用

2 个答案: