关于LEFT JOIN 的问题! SQL TimeOut!
SELECT * FROM table1 LEFT JOIN table2
ON table1.id = table2.id
WHERE table1.name = 'ZHAO' OR table2.name = 'ZHAO'上面很简单的语句,如果table2.name并没有等于'ZHAO'的行,那么这个查询语句就会TimeOut!我想知道这是什么原因?解决办法?
SELECT * FROM table1 LEFT JOIN table2
ON table1.id = table2.id
WHERE table1.name = 'ZHAO' OR table2.name = 'ZHAO'上面很简单的语句,如果table2.name并没有等于'ZHAO'的行,那么这个查询语句就会TimeOut!我想知道这是什么原因?解决办法?
where table1.id = table2.id
and( table1.name = 'ZHAO' OR table2.name = 'ZHAO')
最近很简单的sql都不会了