tp5.1框架数据库子查询操作实例分析

$subQuery = Db::table('think_user')
 ->field('id,name')
 ->where('id', '>', 10)
 ->fetchSql(true)
 ->select();

SELECT `id`,`name` FROM `think_user` WHERE `id` > 10 

$subQuery = Db::table('think_user')
 ->field('id,name')
 ->where('id', '>', 10)
 ->buildSql();

( SELECT `id`,`name` FROM `think_user` WHERE `id` > 10 )

Db::table($subQuery . ' a')
 ->where('a.name', 'like', 'thinkphp')
 ->order('id', 'desc')
 ->select();

SELECT * FROM ( 
 SELECT `id`,`name` FROM `think_user` WHERE `id` > 10 ) a 
WHERE 
 a.name LIKE 'thinkphp' 
ORDER BY 
 `id` 
desc

Db::table('think_user')
 ->where('id', 'IN', function ($query) {
  $query->table('think_profile')->where('status', 1)->field('id');
 })
 ->select();

SELECT * FROM `think_user` 
WHERE `id` IN ( SELECT `id` FROM `think_profile` WHERE `status` = 1 )

Db::table('think_user')
 ->whereExists(function ($query) {
  $query->table('think_profile')->where('status', 1);
 })->find();

SELECT * FROM `think_user` 
WHERE EXISTS ( SELECT * FROM `think_profile` WHERE `status` = 1 )