join sql查询中where和子句的区别 [英] Difference between where and and clause in join sql query

问题描述

以下两个 SQL 查询有什么区别

What is the difference between following two SQL queries

select a.id, a.name, a.country 
from table a 
left join table b on a.id = b.id
where a.name is not null

和

select a.id, a.name, a.country 
from table a 
left join table b on a.id = b.id and a.name is not null

推荐答案

基于以下两个测试结果

select a.id, a.name,a.country from table a left join table b
on a.id = b.id
where a.name is not null 

更快(237 Vs 460).据我所知，这是一个标准.

is faster (237 Vs 460). As far as I know, it is a standard.

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