cms_program表里字段有80多個，數據有300多W，我來時就這樣了~~~額，問領導反應過，，，，額，，，

案例一：

select * from `cms_program` where `fr_dict_epg_status` = 64 and `fr_tb_source` = 2 order by `id` asc limit 50 offset 0

平均12秒左右

優化后的

其實最初的想法是

select * from
(select id from cms_program where `fr_tb_source` = 2)a INNER JOIN cms_program b
on a.id=b.id and? ?b.`fr_dict_epg_status` = 64
order by b.`id` asc limit 50

但方便laravel和with的寫法，改為以下方案

select * from `cms_program` inner join (select `id` from `cms_program` where `fr_tb_source` = 2) as b on `cms_program`.`id` = `b`.`id` where `fr_dict_epg_status` = 64 order by `cms_program`.`id` asc limit 50 offset 0

平均1.5秒

$sub = CMSProgram::select(['id'])->where('fr_tb_source', $kw_source); $builder = CMSProgram::Join(DB::raw("({$sub->toSql()}) as b"), 'cms_program.id', '=', 'b.id')->mergeBindings($sub->getQuery()); $builder = $builder->where('fr_dict_epg_status', '=', Dictionary::getDictIdByKey('db.program.state.online'))->with('partner')->with('type')->with('vt');

案例二：

select id,title,tid,duration_second from `cms_program` where `fr_dict_epg_status` = 64 order by `id` asc limit 50 offset 784050

平均18秒左右

1）limit語句的查詢時間與起始記錄的位置成正比
2）mysql的limit語句是很方便，但是對記錄很多的表并不適合直接使用。

SELECT * FROM cms_program a JOIN (select id from cms_program? where `fr_dict_epg_status` = 64 ORDER BY id asc limit 784050,50) b ON a.ID = b.id

平均0.6秒

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