SQL联表查询注意事项

正常过滤t1表数据行

SELECT  t1.colums FROM t1 LEFT JOIN t2 ON t1.refId = t2.id WHERE t1.isdelete = 0

正常过滤t1表数据行

SELECT  t1.colums FROM t1 INNER JOIN t2 ON t1.refId = t2.id AND t1.isdelete = 0

未能正常过滤t1表数据行

SELECT  t1.colums FROM t1 LEFT JOIN t2 ON t1.refId = t2.id AND t1.isdelete = 0