Oracle 主从表联合查询
表A
id type name
1 E AA
2 F
表B
id Aid name
1 2 BB
2 2 CC
表B 是表A的子表
如果表A中的type是F，就需要根据Aid 去表B里找对应的name，然后拼接起来
数据库是Oracle10G 需要查询的结果：
Aid type name
1 E AA
2 F BB,CC
[解决办法]
with a as(
select 1 id,'E' type,'AA' name from dual
union all
select 2,'F',null from dual
),b as(
select 1 id, 2 aid, 'BB' name from dual
union all
select 2,2,'CC' from dual
)
select a.id, a.type, wm_concat(nvl(a.name, b.name))
from a, b
where a.id = b.aid(+)
group by a.id, a.type;
ID TYPE WM_CONCAT(NVL(A.NAME,B.NAME))
---------- ---- --------------------------------------------
1 E AA
2 F BB,CC
WITH TABLE1 AS(
SELECT '1' AS Aid, 'E' AS type,'AA' as name FROM dual
union all
SELECT '2' AS Aid, 'F' AS type,'' as name FROM dual
union all
SELECT '3' AS Aid, 'F' AS type,'' as name FROM dual
union all
SELECT '4' AS Aid, 'A' AS type,'FF' as name FROM dual
),
TABLE2 AS (
SELECT '1' AS id, '2' AS Aid,'BB' as name FROM dual
union all
SELECT '2' AS id, '2' AS Aid,'CC' as name FROM dual
union all
SELECT '3' AS id, '3' AS Aid,'DD' as name FROM dual
union all
SELECT '4' AS id, '3' AS Aid,'EE' as name FROM dual
)
SELECT T1.Aid,
T1.TYPE,
LISTAGG(nvl(T1.NAME, T2.NAME),',')WITHIN GROUP(ORDER BY id) AS NAME
FROM TABLE1 T1
LEFT JOIN TABLE2 T2 ON T1.Aid = T2.Aid
GROUP BY T1.Aid, T1.TYPE
SELECT T1.NAME
[解决办法]
T2.NAME AS NAME ,T1.* FROM TABLE1 T1 LEFT JOIN (SELECT Aid,LISTAGG(NAME, ',') WITHIN
GROUP(
ORDER BY id) AS NAME FROM TABLE2 GROUP BY Aid) T2 ON T1.Aid = T2.Aid ORDER BY T1.Aid
