我需要从oracle数据库获取数据以在html表中绘制某种矩阵。事实证明，我需要的查询非常复杂且缓慢，因此我决定实现分页。
我关注了许多文章和帖子，但我最喜欢的是这篇文章：On rownum and limiting results
但是它似乎不起作用，执行需要很长时间，就像没有行限制一样，有时甚至需要更长的时间。
请记住，我不是oracle的新手，我已经习惯了MS SQL的最新版本
这是我的查询的简短示例：
SELECT * FROM (
SELECT /*+ FIRST_ROWS(n) */ a.*, ROWNUM rnum FROM (
WITH T1 AS (
SELECT ... FROM VIEW_1
INNER JOIN ...
WHERE ...
GROUP BY ...
),
T2 AS (
SELECT ... FROM VIEW_2
INNER JOIN ...
WHERE ...
GROUP BY ...
),
T3 AS (
SELECT ... FROM VIEW_3
LEFT JOIN ...
WHERE ...
GROUP BY ...
)
SELECT
T1.LVL,
T1.CRSE,
T2.ID,
T3.GRADE
FROM T1
INNER JOIN T2 ON ...
LEFT JOIN T3 ON ...
ORDER BY T2.ID DESC, T1.LVL, T1.CRSE) a
WHERE ROWNUM <= (PAGE * 50))
WHERE rnum >= ((PAGE-1) * 50);
我的实际查询量很大，而且我大多使用无法访问的视图。
我不知道/ * + FIRST_ROWS（n）* /是否像那样工作...而且也不认为我可以在那里设置变量...
我希望执行时间比没有ROWNUM检查的执行时间要短得多，但是它行不通，并且由于GROUP BY的使用，我已经阅读了它。有人可以帮我加快分页速度吗？
编辑： 这是我查询中的EXPLAIN PLAN，希望对您有所帮助：
Plan hash value: 3394899150
-----------------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
-----------------------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 3950 | 648K| | 17918 (1)| 00:03:36 |
|* 1 | VIEW | | 3950 | 648K| | 17918 (1)| 00:03:36 |
|* 2 | COUNT STOPKEY | | | | | | |
| 3 | VIEW | | 8424 | 1275K| | 17918 (1)| 00:03:36 |
| 4 | TEMP TABLE TRANSFORMATION | | | | | | |
| 5 | LOAD AS SELECT | SYS_TEMP_0FD9D6FD2_17D15EA9 | | | | | |
| 6 | HASH UNIQUE | | 36 | 2052 | | 250 (1)| 00:00:03 |
| 7 | VIEW | PS_UAG_ISBI_MAT_VW | 36 | 2052 | | 249 (1)| 00:00:03 |
|* 8 | HASH JOIN | | 36 | 3744 | | 249 (1)| 00:00:03 |
| 9 | NESTED LOOPS | | 34 | 2312 | | 14 (0)| 00:00:01 |
| 10 | NESTED LOOPS | | 44 | 2312 | | 14 (0)| 00:00:01 |
| 11 | NESTED LOOPS | | 1 | 46 | | 5 (0)| 00:00:01 |
| 12 | TABLE ACCESS BY INDEX ROWID | PS_ACAD_PROG_TBL | 1 | 29 | | 4 (0)| 00:00:01 |
|* 13 | INDEX SKIP SCAN | PS1ACAD_PROG_TBL | 1 | | | 3 (0)| 00:00:01 |
|* 14 | INDEX RANGE SCAN | PS1ACAD_ORG_TBL | 1 | 17 | | 1 (0)| 00:00:01 |
|* 15 | INDEX RANGE SCAN | PS2CRSE_OFFER | 44 | | | 1 (0)| 00:00:01 |
|* 16 | TABLE ACCESS BY INDEX ROWID | PS_CRSE_OFFER | 33 | 726 | | 9 (0)| 00:00:01 |
| 17 | VIEW | | 12227 | 429K| | 235 (1)| 00:00:03 |
|* 18 | HASH JOIN RIGHT OUTER | | 12227 | 573K| | 235 (1)| 00:00:03 |
|* 19 | INDEX FAST FULL SCAN | PS_CRSE_ATTRIBUTES | 7690 | 135K| | 98 (0)| 00:00:02 |
| 20 | TABLE ACCESS FULL | PS_CRSE_CATALOG | 12227 | 358K| | 136 (0)| 00:00:02 |
| 21 | LOAD AS SELECT | SYS_TEMP_0FD9D6FD3_17D15EA9 | | | | | |
| 22 | VIEW | | 682 | 36146 | | 1091 (1)| 00:00:14 |
|* 23 | HASH JOIN | | 682 | 41602 | | 1091 (1)| 00:00:14 |
|* 24 | TABLE ACCESS FULL | TYM_TRAYECTORIA | 682 | 17050 | | 513 (1)| 00:00:07 |
| 25 | INDEX FAST FULL SCAN | PS0PERSONAL_DATA | 255K| 8985K| | 577 (1)| 00:00:07 |
| 26 | LOAD AS SELECT | SYS_TEMP_0FD9D6FD4_17D15EA9 | | | | | |
| 27 | HASH GROUP BY | | 107 | 1605 | | 16164 (1)| 00:03:14 |
| 28 | VIEW | | 107 | 1605 | | 16163 (1)| 00:03:14 |
|* 29 | HASH JOIN | | 107 | 2461 | | 16163 (1)| 00:03:14 |
| 30 | VIEW | | 682 | 5456 | | 3 (0)| 00:00:01 |
| 31 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD3_17D15EA9 | 682 | 36146 | | 3 (0)| 00:00:01 |
| 32 | VIEW | PS_UAG_ISBI_CAL_VW | 6411 | 96165 | | 16160 (1)| 00:03:14 |
| 33 | SORT UNIQUE | | 6411 | 7004K| 1960K| 16160 (1)| 00:03:14 |
| 34 | UNION-ALL | | | | | | |
|* 35 | HASH JOIN | | 6342 | 1839K| | 15289 (1)| 00:03:04 |
|* 36 | INDEX FAST FULL SCAN | PS_CRSE_ATTRIBUTES | 7690 | 135K| | 98 (0)| 00:00:02 |
|* 37 | HASH JOIN | | 4943 | 1346K| | 15191 (1)| 00:03:03 |
|* 38 | HASH JOIN | | 4943 | 1168K| | 10790 (1)| 00:02:10 |
| 39 | INDEX FAST FULL SCAN | PS1TERM_TBL | 1256 | 31400 | | 4 (0)| 00:00:01 |
|* 40 | HASH JOIN | | 4943 | 1047K| | 10786 (1)| 00:02:10 |
| 41 | INDEX FAST FULL SCAN | PS0CRSE_CATALOG | 12227 | 358K| | 31 (0)| 00:00:01 |
|* 42 | HASH JOIN | | 4985 | 910K| | 10755 (1)| 00:02:10 |
| 43 | TABLE ACCESS FULL | PS_ACAD_ORG_TBL | 549 | 23058 | | 7 (0)| 00:00:01 |
|* 44 | HASH JOIN | | 5297 | 750K| 2856K| 10748 (1)| 00:02:09 |
| 45 | TABLE ACCESS FULL | PS_CLASS_TBL | 52112 | 2239K| | 650 (1)| 00:00:08 |
|* 46 | HASH JOIN | | 100K| 9893K| | 9422 (1)| 00:01:54 |
| 47 | TABLE ACCESS FULL | PS_ACAD_PROG_TBL | 313 | 18467 | | 5 (0)| 00:00:01 |
|* 48 | TABLE ACCESS FULL | PS_STDNT_ENRL | 986K| 39M| | 9414 (1)| 00:01:53 |
| 49 | TABLE ACCESS FULL | PS_PERSONAL_DATA | 255K| 9235K| | 4400 (1)| 00:00:53 |
| 50 | NESTED LOOPS | | 69 | 19596 | | 462 (1)| 00:00:06 |
| 51 | NESTED LOOPS | | 69 | 19596 | | 462 (1)| 00:00:06 |
|* 52 | HASH JOIN | | 69 | 17043 | | 324 (1)| 00:00:04 |
|* 53 | HASH JOIN | | 69 | 15318 | | 320 (1)| 00:00:04 |
|* 54 | HASH JOIN | | 105 | 21420 | | 222 (1)| 00:00:03 |
|* 55 | HASH JOIN | | 101 | 17574 | | 191 (1)| 00:00:03 |
|* 56 | HASH JOIN | | 101 | 14443 | | 88 (0)| 00:00:02 |
|* 57 | HASH JOIN | | 314 | 31714 | | 12 (0)| 00:00:01 |
| 58 | TABLE ACCESS FULL | PS_ACAD_PROG_TBL | 313 | 18467 | | 5 (0)| 00:00:01 |
| 59 | TABLE ACCESS FULL | PS_ACAD_ORG_TBL | 549 | 23058 | | 7 (0)| 00:00:01 |
| 60 | VIEW | | 7540 | 309K| | 76 (0)| 00:00:01 |
|* 61 | HASH JOIN | | 7540 | 493K| | 76 (0)| 00:00:01 |
| 62 | TABLE ACCESS FULL | PS_TRNS_CRSE_SCH | 597 | 16119 | | 6 (0)| 00:00:01 |
| 63 | TABLE ACCESS FULL | PS_TRNS_CRSE_DTL | 7540 | 294K| | 70 (0)| 00:00:01 |
| 64 | TABLE ACCESS FULL | PS_CRSE_OFFER | 12227 | 370K| | 102 (0)| 00:00:02 |
| 65 | INDEX FAST FULL SCAN | PS0CRSE_CATALOG | 12227 | 358K| | 31 (0)| 00:00:01 |
|* 66 | INDEX FAST FULL SCAN | PS_CRSE_ATTRIBUTES | 7690 | 135K| | 98 (0)| 00:00:02 |
| 67 | INDEX FAST FULL SCAN | PS1TERM_TBL | 1256 | 31400 | | 4 (0)| 00:00:01 |
|* 68 | INDEX UNIQUE SCAN | PS_PERSONAL_DATA | 1 | | | 1 (0)| 00:00:01 |
| 69 | TABLE ACCESS BY INDEX ROWID | PS_PERSONAL_DATA | 1 | 37 | | 2 (0)| 00:00:01 |
|* 70 | SORT ORDER BY STOPKEY | | 8424 | 1628K| 1736K| 413 (1)| 00:00:05 |
|* 71 | HASH JOIN RIGHT OUTER | | 8424 | 1628K| | 46 (5)| 00:00:01 |
| 72 | VIEW | | 108 | 2700 | | 2 (0)| 00:00:01 |
| 73 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD4_17D15EA9 | 108 | 1620 | | 2 (0)| 00:00:01 |
|* 74 | HASH JOIN RIGHT OUTER | | 78 | 13494 | | 44 (5)| 00:00:01 |
| 75 | VIEW | | 26 | 390 | | 24 (5)| 00:00:01 |
| 76 | HASH GROUP BY | | 26 | 702 | | 24 (5)| 00:00:01 |
| 77 | VIEW | | 47 | 1269 | | 24 (5)| 00:00:01 |
| 78 | HASH GROUP BY | | 47 | 2256 | | 24 (5)| 00:00:01 |
|* 79 | HASH JOIN OUTER | | 47 | 2256 | | 23 (0)| 00:00:01 |
|* 80 | HASH JOIN OUTER | | 47 | 1081 | | 21 (0)| 00:00:01 |
| 81 | VIEW | | 36 | 360 | | 2 (0)| 00:00:01 |
| 82 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD2_17D15EA9 | 36 | 2052 | | 2 (0)| 00:00:01 |
| 83 | TABLE ACCESS FULL | PS_RQ_GRP_DETL_TBL | 2702 | 35126 | | 19 (0)| 00:00:01 |
| 84 | VIEW | | 108 | 2700 | | 2 (0)| 00:00:01 |
| 85 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD4_17D15EA9 | 108 | 1620 | | 2 (0)| 00:00:01 |
|* 86 | HASH JOIN RIGHT OUTER | | 78 | 12324 | | 20 (5)| 00:00:01 |
| 87 | TABLE ACCESS FULL | PS_UAG_PRECARG_SUBJECT | 12 | 168 | | 3 (0)| 00:00:01 |
|* 88 | HASH JOIN RIGHT OUTER | | 78 | 11232 | | 17 (6)| 00:00:01 |
| 89 | VIEW | | 1 | 20 | | 12 (9)| 00:00:01 |
| 90 | HASH GROUP BY | | 1 | 30 | | 12 (9)| 00:00:01 |
| 91 | VIEW | PS_UAG_OFERCRSE_VW | 1 | 30 | | 12 (9)| 00:00:01 |
| 92 | HASH UNIQUE | | 1 | 213 | | 12 (9)| 00:00:01 |
| 93 | NESTED LOOPS OUTER | | 1 | 213 | | 11 (0)| 00:00:01 |
| 94 | NESTED LOOPS OUTER | | 1 | 177 | | 9 (0)| 00:00:01 |
| 95 | NESTED LOOPS OUTER | | 1 | 139 | | 6 (0)| 00:00:01 |
|* 96 | TABLE ACCESS BY INDEX ROWID| PS_CLASS_TBL | 1 | 69 | | 4 (0)| 00:00:01 |
|* 97 | INDEX RANGE SCAN | PSDCLASS_TBL | 1 | | | 3 (0)| 00:00:01 |
| 98 | TABLE ACCESS BY INDEX ROWID| PS_CLASS_MTG_PAT | 1 | 70 | | 2 (0)| 00:00:01 |
|* 99 | INDEX RANGE SCAN | PS_CLASS_MTG_PAT | 1 | | | 1 (0)| 00:00:01 |
| 100 | TABLE ACCESS BY INDEX ROWID | PS_CLASS_INSTR | 1 | 38 | | 3 (0)| 00:00:01 |
|*101 | INDEX RANGE SCAN | PS_CLASS_INSTR | 1 | | | 2 (0)| 00:00:01 |
| 102 | TABLE ACCESS BY INDEX ROWID | PS_PERSONAL_DATA | 1 | 36 | | 2 (0)| 00:00:01 |
|*103 | INDEX UNIQUE SCAN | PS_PERSONAL_DATA | 1 | | | 1 (0)| 00:00:01 |
| 104 | VIEW | | 78 | 9672 | | 5 (0)| 00:00:01 |
|*105 | HASH JOIN | | 78 | 10140 | | 5 (0)| 00:00:01 |
| 106 | VIEW | | 36 | 2988 | | 2 (0)| 00:00:01 |
| 107 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD2_17D15EA9 | 36 | 2052 | | 2 (0)| 00:00:01 |
| 108 | VIEW | | 682 | 32054 | | 3 (0)| 00:00:01 |
| 109 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6FD3_17D15EA9 | 682 | 36146 | | 3 (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
1 - filter("RNUM">=0)
2 - filter(ROWNUM<=3950)
8 - access("D"."CRSE_ID"="C"."CRSE_ID")
13 - access("A"."ACAD_PROG"='LMC09')
filter("A"."ACAD_PROG"='LMC09')
14 - access("B"."INSTITUTION"="A"."INSTITUTION" AND "B"."ACAD_ORG"="A"."ACAD_ORG")
15 - access("C"."SUBJECT"="A"."ACAD_PLAN")
16 - filter("C"."INSTITUTION"="A"."INSTITUTION")
18 - access("E"."CRSE_ID"(+)="D"."CRSE_ID")
19 - filter("E"."CRSE_ATTR"(+)='0003')
23 - access("PERS"."EMPLID"="TRA"."EMPLID")
24 - filter("TRA"."STRM"='1835' AND "TRA"."ACAD_PLAN"='LMC09')
29 - access("A2"."EMPLID"="CAL"."EMPLID")
35 - access("F"."CRSE_ID"="E"."CRSE_ID")
36 - filter("F"."CRSE_ATTR"='0003')
37 - access("B"."EMPLID"="A"."EMPLID")
38 - access("H"."INSTITUTION"="A"."INSTITUTION" AND "H"."ACAD_CAREER"="A"."ACAD_CAREER" AND "H"."STRM"="A"."STRM")
40 - access("E"."CRSE_ID"="C"."CRSE_ID")
42 - access("G"."INSTITUTION"="A"."INSTITUTION" AND "G"."ACAD_ORG"="D"."ACAD_ORG")
44 - access("C"."INSTITUTION"="A"."INSTITUTION" AND "C"."ACAD_CAREER"="A"."ACAD_CAREER" AND "C"."STRM"="A"."STRM" AND
"C"."CLASS_NBR"="A"."CLASS_NBR" AND "C"."SESSION_CODE"="A"."SESSION_CODE")
46 - access("D"."INSTITUTION"="A"."INSTITUTION" AND "D"."ACAD_CAREER"="A"."ACAD_CAREER" AND
"D"."ACAD_PROG"="A"."ACAD_PROG")
48 - filter("A"."STDNT_ENRL_STATUS"='E')
52 - access("H"."INSTITUTION"="A"."INSTITUTION" AND "H"."ACAD_CAREER"="A"."ACAD_CAREER" AND
"H"."STRM"="A"."ARTICULATION_TERM")
53 - access("F"."CRSE_ID"="E"."CRSE_ID")
54 - access("E"."CRSE_ID"="C"."CRSE_ID")
55 - access("C"."INSTITUTION"="A"."INSTITUTION" AND "C"."ACAD_CAREER"="A"."ACAD_CAREER" AND "C"."CRSE_ID"="A"."CRSE_ID")
56 - access("D"."INSTITUTION"="A"."INSTITUTION" AND "D"."ACAD_CAREER"="A"."ACAD_CAREER" AND
"D"."ACAD_PROG"="A"."ACAD_PROG" AND "G"."INSTITUTION"="A"."INSTITUTION")
57 - access("G"."ACAD_ORG"="D"."ACAD_ORG")
61 - access("B"."EMPLID"="A"."EMPLID" AND "B"."ACAD_CAREER"="A"."ACAD_CAREER" AND "B"."INSTITUTION"="A"."INSTITUTION"
AND "B"."MODEL_NBR"="A"."MODEL_NBR")
66 - filter("F"."CRSE_ATTR"='0003')
68 - access("B"."EMPLID"="A"."EMPLID")
70 - filter(ROWNUM<=3950)
71 - access("C3"."CRSE_ID"(+)="from$_subquery$_019"."CRSE_ID" AND "C3"."EMPLID"(+)="from$_subquery$_019"."EMPLID")
74 - access("R3"."EMPLID"(+)="from$_subquery$_019"."EMPLID" AND
"R3"."RQRMNT_GROUP"(+)="from$_subquery$_019"."RQRMNT_GROUP")
filter("from$_subquery$_019"."RQRMNT_GROUP"<>CASE WHEN ("R3"."RQRMNT_GROUP"(+) IS NOT NULL) THEN ' ' ELSE ' ' END )
79 - access("REQ"."CRSE_ID"="C2"."CRSE_ID"(+))
80 - access("REQ"."RQRMNT_GROUP"(+)="M2"."RQRMNT_GROUP")
filter("M2"."RQRMNT_GROUP"<>CASE WHEN ("REQ"."RQRMNT_GROUP"(+) IS NOT NULL) THEN ' ' ELSE ' ' END )
86 - access("DTL"."CRSE_ID"(+)="M3"."CRSE_ID" AND "A3"."IDTRAYECTORIA"=TO_NUMBER("DTL"."ID_TRAYECTORIA"(+)))
88 - access("H3"."CRSE_ID"(+)="from$_subquery$_019"."CRSE_ID")
96 - filter("A"."SESSION_CODE"='ORD' AND "A"."CLASS_STAT"='A')
97 - access("A"."SUBJECT"='LMC09' AND "A"."STRM"='1853')
99 - access("B"."CRSE_ID"(+)="A"."CRSE_ID" AND "B"."CRSE_OFFER_NBR"(+)="A"."CRSE_OFFER_NBR" AND "B"."STRM"(+)='1853' AND
"B"."SESSION_CODE"(+)='ORD' AND "B"."CLASS_SECTION"(+)="A"."CLASS_SECTION")
101 - access("C"."CRSE_ID"(+)="B"."CRSE_ID" AND "C"."CRSE_OFFER_NBR"(+)="B"."CRSE_OFFER_NBR" AND "C"."STRM"(+)="B"."STRM"
AND "C"."SESSION_CODE"(+)="B"."SESSION_CODE" AND "C"."CLASS_SECTION"(+)="B"."CLASS_SECTION" AND
"C"."CLASS_MTG_NBR"(+)="B"."CLASS_MTG_NBR")
103 - access("D"."EMPLID"(+)="C"."EMPLID")
105 - access("M3"."ACAD_PLAN"="A3"."ACAD_PLAN")
编辑2，解决方案： 我设法使用以下查询找到已为表“ PS_STDNT_ENRL”配置的索引：
SELECT
index_owner, index_name, table_name, column_name, column_position
FROM DBA_IND_COLUMNS
WHERE table_name = 'PS_STDNT_ENRL'
ORDER BY
index_owner,
table_name,
index_name,
column_position;
并在我的WHERE子句中找到所需的列，以便索引正常工作。 我修改了查询，现在查询非常快。
答案 0 :(得分：0)
ROWNUM仅限制查询运行并返回所有行后显示的行数。因此，它仍然在做所有工作。
如果t1.id是数字，则可以使用MOD（）减少前期工作量，并轻松将结果按需要分成多个部分。例如，针对t1.id的MOD（）为5，可以将结果分成5个部分，分别对应于MOD（）的0、1、2、3、4。
SELECT MOD(/*t1.id*/1000,5) FROM dual;
通过这种方式，您减少了驱动表（t1）中考虑的行数，因此在加入其他表之后要管理的数据更少。
它看起来像这样：
AND MOD(t1.id,5) =
00 -- Partition 1
-- 01 -- Partition 2
-- 02 -- Partition 3
-- 03 -- Partition 4
-- 04 -- Partition 5