我看了一下in 和 exists产生执行计划的区别，从谓词从看到exists需要没有展开，所以我加了一个Hint验证了一下，执行结果跟in就是一样的了。
--unnest为展开子查询
SQL> SELECT *
FROM (SELECT DISTINCT A.*
FROM GG_MATERIAL_CLASSIFY A
CONNECT BY PRIOR PARENT_CLASSIFY_ID = CLASSIFY_ID
START WITH exists
(SELECT /*+unnest*/DISTINCT M.CLASSIFY_ID
FROM GG_DISTRIBUTION D, GG_MATERIAL M
WHERE D.MATERIAL_ID = M.MATERIAL_ID
AND A.CLASSIFY_ID=M.CLASSIFY_ID
AND D.ACTUAL_QTY > 0
AND D.DATA_AREA LIKE '03%')) B
WHERE B.PARENT_CLASSIFY_ID = '201'
ORDER BY B.CODE ASC;
已选择11行。
已用时间: 00: 00: 01.18
执行计划
----------------------------------------------------------
Plan hash value: 2653190462
----------------------------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time | Pstart| Pstop |
----------------------------------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 3246 | 3445K| | 16641 (1)| 00:03:20 | | |
| 1 | SORT ORDER BY | | 3246 | 3445K| | 16641 (1)| 00:03:20 | | |
|* 2 | VIEW | | 3246 | 3445K| | 16641 (1)| 00:03:20 | | |
| 3 | HASH UNIQUE | | 3246 | 653K| | 16641 (1)| 00:03:20 | | |
|* 4 | CONNECT BY WITHOUT FILTERING (UNIQUE) | | | | | | | | |
|* 5 | HASH JOIN SEMI | | 1623 | 256K| | 16626 (1)| 00:03:20 | | |
| 6 | TABLE ACCESS FULL | GG_MATERIAL_CLASSIFY | 1864 | 262K| | 14 (0)| 00:00:01 | | |
| 7 | VIEW | VW_SQ_1 | 144K| 2533K| | 16610 (1)| 00:03:20 | | |
|* 8 | HASH JOIN | | 144K| 6051K| 3784K| 16610 (1)| 00:03:20 | | |
| 9 | INDEX FAST FULL SCAN | INX_GG_MATERIAL_CLASSIFY | 117K| 2403K| | 145 (2)| 00:00:02 | | |
|* 10 | TABLE ACCESS BY GLOBAL INDEX ROWID| GG_DISTRIBUTION | 144K| 3097K| | 16045 (1)| 00:03:13 | ROWID | ROWID |
|* 11 | INDEX RANGE SCAN | IX_DISTRIBU_ACT_QTY01 | 144K| | | 346 (1)| 00:00:05 | | |
| 12 | TABLE ACCESS FULL | GG_MATERIAL_CLASSIFY | 1864 | 262K| | 14 (0)| 00:00:01 | | |
----------------------------------------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
2 - filter("B"."PARENT_CLASSIFY_ID"='201')
4 - access("CLASSIFY_ID"=PRIOR "PARENT_CLASSIFY_ID")
5 - access("A"."CLASSIFY_ID"="ITEM_0")
8 - access("D"."MATERIAL_ID"="M"."MATERIAL_ID")
10 - filter("D"."DATA_AREA" LIKE '03%')
11 - access("D"."ACTUAL_QTY">0)
统计信息
----------------------------------------------------------
1 recursive calls
0 db block gets
113928 consistent gets
0 physical reads
0 redo size
1960 bytes sent via SQL*Net to client
338 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
11 rows processed