使用条件案例语句的SQL搜索

Question

I need to perform a search based on condition. If I pass @SearchCondition = 1 then the search should be performed on OrderId column for the passed @SearchValue If I pass @SearchCondition = 0 the search must return all the records minus the record with @SearchValue

IF @SearchCondition = 1 
   Search Records With [OrderId] = @SearchValue

IF @SearchCondition = 0 
   Get All The Records With [OrderId] <> @SearchValue

But the above needs to be done in a single statement (ideally CASE statement). No IF-ELSE since the query is too big and I do not want to write the same long query twice but with only a single different line. Here is the sample table for convenience:

DECLARE @SearchCondition INT = 0, @SearchValue INT = 121 
CREATE TABLE #TempData
(
[Id] INT IDENTITY(1,1),
[OrderId] INT,
[OrderName] VARCHAR(20)
)
INSERT INTO #TempData
SELECT 121, 'A1' UNION
SELECT 122, 'A2' UNION
SELECT 123, 'A3' UNION
SELECT 124, 'A4' UNION
SELECT 125, 'A5' UNION
SELECT 126, 'A6' UNION
SELECT 127, 'A7' UNION
SELECT 128, 'A8' UNION
SELECT 129, 'A9' UNION
SELECT 130, 'A10'   

--If SearchCondition = 1
SELECT [Id], [OrderId], [OrderName] 
FROM #TempData
WHERE [OrderId] = @SearchValue--If SearchCondition = 1
-- Handle If SearchCondition = 0
--SELECT [Id], [OrderId], [OrderName] 
--FROM #TempData
--WHERE [OrderId] <> @SearchValue

DROP TABLE #TempData

Need to merge the above statements in a single statement

Answer 1

This is called a Catch-all Query . One way is to use AND-OR combinations

SELECT [Id], [OrderId], [OrderName] 
FROM #TempData
WHERE 
    (@SearchCondition = 1 AND [OrderId] = @SearchValue)
    OR (@SearchCondition = 0 AND [OrderId] <> @SearchValue)

Additional Reading:

• Dynamic Search Conditions in T-SQL by Erland Sommarskog

Answer 2

WHERE ([OrderId] = 
case when  @SearchCondition=1 then @SearchValue  end)
or ([OrderId] <>
case when  @SearchCondition=0 then @SearchValue  end)