sql-server - SQL Server 使用 not in 加速查询

Question

我有一个名为sales以下几列的表：

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

现在我想选择所有salesno不在的行advanceno：

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

查询很慢，因为 sales 表有数十万行。

我这样做了，而且速度非常快：

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