Question

有两张桌子节点：

nid INT(10)
type (VARCHAR(32))

node_hit_count

nid INT(10)
totalcount (bigint(20))

我需要从nid表中选择node表中不在node_hit_count表格中的所有WHERE，node feature类型等于{{1} }或home或competition

我尝试过，错了，我的思绪会被打击：/

select * from node left join node_hit_counter on node.nid=node_hit_counter.nid 

where hit.nid is null and node.type IN ('feature', 'home', 'competition')

Answer 1

hit.nid子句中的WHERE是什么。您必须使用WHERE node.nid IS NULL，而不是这样：

select node.*
from node 
left join node_hit_counter on node.nid = node_hit_counter.nid 
where node.nid is null 
  and node.type IN ('feature', 'home', 'competition');

或

SELECT * FROM node WHERE nid NOT IN(SELECT nid FROM node_hit_counter WHERE nid IS NOT NULL) AND type IN ('feature', 'home', 'competition');

Answer 2

试试这个，你可以在where子句中使用你的hit.nid：o）

select n.* 
from node n
left join node_hit_counter hit on n.nid=hit.nid 
where hit.nid is null 
and n.type IN ('feature', 'home', 'competition')

从表中选择不在另一个有条件的表中

2 个答案: