帮忙看个SQL问题
SELECT ornamentation_images.ismark ismark,ornamentation_images.width width,ornamentation_images.height height,users.nickname name,ornamentations.id id,ornamentations.image_name image_name,ornamentations.image_url image_url,ornamentations.add_author add_author,ornamentations.browse_real_cnt browse_real_cnt,ornamentations.comnum comnum,users.head head,users.comnum unreadFROM `ornamentation_images` LEFT JOIN users on ornamentation_images.add_author=users.id LEFT JOIN ornamentations on ornamentation_images.ornamentation_id=ornamentations.id WHERE ( ornamentations.enable = 0 ) AND ( ornamentations.checkstatus = 2 ) ORDER BY ornamentations.id desc LIMIT 0,5
能查出来结果,只是没有查出来users表里的数据,问题出在哪?
回复讨论(解决方案)
表结构在哪呢
可能是left join 的问题
left join是以左表的记录为基础的,ornamentation_images可以看成左表,users可以看成右表,left join是以左表为准的.
换句话说,左表的记录将会全部表示出来,而右表只会显示符合搜索条件的记录,右表记录不足的地方均为NULL.
楼主可以查看一下,是否这个原因呢
表结构在哪呢
users表在ornamentation_images上,ornamentations也在ornamentation_images上
可能是left join 的问题
left join是以左表的记录为基础的,ornamentation_images可以看成左表,users可以看成右表,left join是以左表为准的.
换句话说,左表的记录将会全部表示出来,而右表只会显示符合搜索条件的记录,右表记录不足的地方均为NULL.
楼主可以查看一下,是否这个原因呢
不是,换了right和inner都不行
可能是left join 的问题
left join是以左表的记录为基础的,ornamentation_images可以看成左表,users可以看成右表,left join是以左表为准的.
换句话说,左表的记录将会全部表示出来,而右表只会显示符合搜索条件的记录,右表记录不足的地方均为NULL.
楼主可以查看一下,是否这个原因呢
找到问题了,是where的问题,把where条件去掉就有了。但是必须要带where呀,该怎么写呢?
那应该是表中没有符合这个where条件的记录
那应该是表中没有符合这个where条件的记录
恩,的确是数据库问题,sql没问题,结贴
一个可能是你关联user表错误另一个就是在你当前where条件下user表里面没有数据满足

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