如何删除** IN **查询Sql中的冗余条件

Question

我有这种查询。但我需要优化此查询，以便如何省略具有相同拆分功能的冗余条件。

DECLARE @Filter nvarchar(20)
SELECT @Filter ='5,22,3'

SELECT * FROM    Employee e
             WHERE e.code IN 
             (
             CASE WHEN((SELECT count(*) FROM dbo.FNSPLITSTRING(SUBSTRING(@Filter,1,LEN(@Filter)-1), ',') d 
                                  WHERE d.splitdata IN (5, 16, 20, 23, 33, 49, 62, 90, 91, 92, 93, 94))>0) THEN 5 ELSE 0 END 
             ,CASE WHEN((SELECT count(*) FROM dbo.FNSPLITSTRING(SUBSTRING(@Filter,1,LEN(@Filter)-1), ',') d 
                                  WHERE d.splitdata IN (22, 18))>0) THEN 46 ELSE 0 END
             ,CASE WHEN((SELECT count(*) FROM dbo.FNSPLITSTRING(SUBSTRING(@Filter,1,LEN(@Filter)-1), ',') d 
                                  WHERE d.splitdata IN (3, 28))>0) THEN 3 ELSE 0 END
             )

Answer 1

正如@Damien_The_Unbeliever所说，避免将字符串拆分为值表。您不需要多次拆分相同的字符串。相反，您可以使用临时表变量。

DECLARE @SplitStrings TABLE
(
    splitdata int
)

INSERT @SplitStrings
SELECT splitdata FROM dbo.FNSPLITSTRING(SUBSTRING(@Filter,1,LEN(@Filter)-1), ',') d

DECLARE @EmployeeCodes TABLE
(
    splitdata INT,
    code int
)

INSERT @EmployeeCodes (splitdata, code)
VALUES (5, 5), (16, 5), (20, 5), (23, 5), (33, 5), (49, 5), (62, 5), (90, 5), (91, 5), (92, 5), (93, 5), (94, 5), 
       (22, 46), (18, 46),
       (3, 3), (28, 3)


SELECT e.* 
FROM Employee e
JOIN @EmployeeCodes ec
ON e.code = ec.code
JOIN @SplitStrings ss
ON ec.splitdata = ss.splitdata

我希望这是你正在看的方向。

注意：假设您不需要0作为员工代码。

Answer 2

我做了新方法。不那么复杂，省略冗余代码。

DECLARE @Filter nvarchar(20)
SELECT @Filter ='5,22,3'

SELECT Distinct e.EmployeeId FROM Employee e
CROSS JOIN dbo.fnSplitString(@Filter, ',') AS d
WHERE 
(e.code = 5 AND d.splitdata IN ('5', '16', '20', '23', '33', '49', '62', '90', '91', '92', '93', '94'))
OR (e.code = 46 AND d.splitdata IN ('22', '18'))
OR (e.code = 3 AND d.splitdata IN ('3', '28'))