急！在线等！mysql右表引用左表字段值的问题？
SQLServer中有这样的语句：
SELECT
a.col1, b.col1, b.col2
FROM ta a
CROSS APPLY (
SELECT
tb.col1, tb.col2
FROM tb
WHERE tb.col3 = a.col1
)b
GROUP BY a.col1;
这样的语句，mysql怎么实现？？
SELECT a.col1, b.col1, b.col2
FROM tb b inner join ta a on b.col3 = a.col1
CROSS APPLY：类似INNER JOIN
SELECT a.col1, b.col1, b.col2
FROM tb b inner join ta a on b.col3 = a.col1
引用不要 join，我最初用的是join，性能很差！！！
