LATERAL VIEW EXPLODE与LATERAL VIEW OUTER EXPLODE的区别
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LATERAL VIEW EXPLODE与LATERAL VIEW OUTER EXPLODE的区别
- LATERAL VIEW EXPLODE 当需要拆分的字段为null时，null的那行数据不会出现在结果
- LATERAL VIEW OUTER EXPLODE 所有行都会显示在结果集中（包含要拆分的字段为null时）
LATERAL VIEW EXPLODE ：
SELECT a.c1,
a.c2,
b.c22
FROM (
SELECT '1' AS c1,
'a,b,c' AS c2
UNION ALL
SELECT '2' AS c1,
NULL AS c2
UNION ALL
SELECT '3' AS c1,
'' AS c2
) a
LATERAL VIEW
EXPLODE(split(a.c2, ',')) b AS c22;
结果：
c1 c2 c22
1 a,b,c a
1 a,b,c b
1 a,b,c c
3
LATERAL VIEW OUTER EXPLODE :
SELECT a.c1,
a.c2,
b.c22
FROM (
SELECT '1' AS c1,
'a,b,c' AS c2
UNION ALL
SELECT '2' AS c1,
NULL AS c2
UNION ALL
SELECT '3' AS c1,
'' AS c2
) a
LATERAL VIEW OUTER
EXPLODE(split(a.c2, ',')) b AS c22;
结果：
c1 c2 c22
1 a,b,c a
1 a,b,c b
1 a,b,c c
3
2 NULL NULL
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