mysql中join后on、where的区别

SELECT * FROM A;sql SELECT * FROM B; 以上是两张表的机构3d   SELECT * FROM A LEFT JOIN B ON A.id=b.a_id ; 语句一 : SELECT * FROM A LEFT JOIN B ON A.id=b.a_id AND A.id <3; 语句二: SELECT * FROM A LEFT JOIN B ON A
相关文章
相关标签/搜索