多表查询的sql语句
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2024-01-29 11:38:46
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求一个多表查询的sql语句
A表10个字段
字段分别为aid, title, cid, content, atime, aorder, acount,a1, a2, mtime
B表9个字段
字段分别为bid, title, cid, content, btime, border, b3, b4, mtime
现在我获取到一个关键词$kw,我需要同时搜索A表和B表的title字段,获取到所有like %$kw%的所有记录,并根据mtime来排序。
获取的记录里,需要保留的字段有a(b)id,title,cid,content,mtime这几个。
我这样构造sql,可行吗?
如果不可行,那么怎么写这个sql语句呢?
------解决方案--------------------
去看一下 union
两个 select 然后中间用一下 union , 要求 select 后面的字段都一样的
select a.id, a.xxx from a where a.title like '%$km%'
union
select b.id, b.xxx from b where b.title like '%$km%'
------解决方案--------------------
select aid, title, cid, content,mtime from a where title like '%km%'
order by mtime desc
union all
select bid,title,cid,content,mtime from b where title like '%km%'
order by mtime desc
A表10个字段
字段分别为aid, title, cid, content, atime, aorder, acount,a1, a2, mtime
B表9个字段
字段分别为bid, title, cid, content, btime, border, b3, b4, mtime
现在我获取到一个关键词$kw,我需要同时搜索A表和B表的title字段,获取到所有like %$kw%的所有记录,并根据mtime来排序。
获取的记录里,需要保留的字段有a(b)id,title,cid,content,mtime这几个。
- SQL code
$sql = 'SELECT ';$sql .= 'A.aid as id,B.bid AS id,';$sql .= 'A.title as title,B.title as title,';$sql .= 'A.cid as cid,B.cid as cid,';$sql .= 'A.content as content,B.content as content,';$sql .= 'A.mtime as mtime,B.mtime as mtime';$sql .= 'FROM A,B WHERE title like "%'.$kw.'%" ORDER BY mtime DESC';
我这样构造sql,可行吗?
如果不可行,那么怎么写这个sql语句呢?
------解决方案--------------------
去看一下 union
两个 select 然后中间用一下 union , 要求 select 后面的字段都一样的
select a.id, a.xxx from a where a.title like '%$km%'
union
select b.id, b.xxx from b where b.title like '%$km%'
------解决方案--------------------
select aid, title, cid, content,mtime from a where title like '%km%'
order by mtime desc
union all
select bid,title,cid,content,mtime from b where title like '%km%'
order by mtime desc
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