《Mysql学习mysql多表子查询与左连接的代码》要点:
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导读:本节内容:mysql多表子查询与左连接需求:如何在mysql中实现复杂查询、多表查询包含子连接的?解决方法:
select c.*,d1.debt,d2.hasorders...
MYSQL应用本节内容:
mysql多表子查询与左连接
MYSQL应用需求:
如何在mysql中实现复杂查询、多表查询包含子连接的?
MYSQL应用解决方法:
select c.*,d1.debt,d2.hasorders from dw_customerinfo c left join (select d.customerid, sum(d.price)>sum(d.pay) debt from dw_ordersdetail d where d.state='1' and d.pubtime<= now() group by d.customerid) d1 on c.id=d1.customerid
left join (select d.customerid, count(d.customerid)>0 hasorders from dw_ordersdetail d group by d.customerid) d2 on c.id=d2.customerid
MYSQL应用方法1:测试未通过
Select * FROM t1 LEFT JOIN (t2, t3, t4) ON (t2.a=t1.a AND t3.b=t1.b AND t4.c=t1.c)
MYSQL应用方法2:测试通过
SELECT artists.Artist, cds.title, genres.genre
FROM cds
LEFT JOIN genres N cds.genreID = genres.genreID
LEFT JOIN artists ON cds.artistID = artists.artistID;
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