Question

我有一个名为sales的表，其中包含以下几列：

salesno (PK, char(25))
advanceno (char(15), not null)

现在我要选择salesno中advanceno不在的所有行：

SELECT salesno 
FROM sales 
WHERE salesno NOT IN (SELECT advanceno FROM sales)

查询很慢，因为sales表有几十万行。

我这样做了，速度非常快：

SELECT salesno 
FROM sales 
WHERE salesno NOT IN ('000008360', '000008361', '000008362', '000008363', '000008364')

如何优化查询？

Answer 1

试试这个：

DECLARE @sales as Table (salesno char(25)
,advanceno char(15) not null)

INSERT INTO @sales(salesno,advanceno)
SELECT '000008360','000008360' UNION ALL
SELECT '000008361','000008362' UNION ALL
SELECT '000008362','000008364' 

SELECT  s.salesno 
FROM    @sales s 
LEFT JOIN @sales a ON a.advanceno = s.salesno
WHERE   a.advanceno IS NULL

在你的例子中，试试这个

SELECT  s.salesno 
FROM    sales s 
LEFT JOIN sales a ON a.advanceno = s.salesno
WHERE   a.advanceno IS NULL

SQL Server加速查询不在

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