sql leftjoin多表查询,出现重复的数据,怎么办答:SQL codeCREATE TABLE #A表 (ID INT,TYPEA CHAR(10))INSERT #A表 SELECT '1','1' UNION ALL SELECT '2','1' UNION ALL SELECT '3','2'CREATE TABLE #B表 (ID INT,CLASS CHAR(10))INSERT #B表 SELECT '1','1' UNION ALL SELECT '2','2' UNION ALL SELECT '4','4' UNION...