今天研究了两个表中外连接条件位置不同,导致的查询结果不同,
---DROP TABLE #t1,#t2
---创建表1
CREATE TABLE #t1(areaid NVARCHAR(20),housecode NVARCHAR(20),expressid INT)
INSERT INTO #t1(areaid, housecode, expressid )VALUES ('101','01', 1)
INSERT INTO #t1(areaid, housecode, expressid )VALUES ('101','02', 1)
INSERT INTO #t1(areaid, housecode, expressid )VALUES ('101','03', 1)
INSERT INTO #t1(areaid, housecode, expressid )VALUES ('101','04', 1)
--创建表2
CREATE TABLE #t2(a......
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