mysql中join后on、where的区别

SELECT * FROM A; SELECT * FROM B; 以上是两张表的机构 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 ❤️; 语句二： SELECT * FROM A LEFT JOIN B ON A.id=b.a_id W

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