我有一个例子:
我有一个查询:
SQL1
SELECT a.`name` as AName, b.`name`as BName
FROM A a
LEFT JOIN B b
ON (b.a_id = a.id AND b.a_id = `specific value`)
SQL2:
SELECT a.`name` as AName, b.`name`as BName
FROM A a
LEFT JOIN B b ON (b.a_id = a.id)
WHERE b.a_id = `specific value`
SQL1 (2条记录)与 SQL2 (0条记录)
的结果有人知道为什么吗?你能为我解释一下吗?