我正在尝试编写一个Oracle查询以联接来自4个不同表的数据。代码如下：
SELECT
PROJ.PRJ_NO, PROJ.PRJ_NAME, PROJ.PRJ_BEG_DATE, PROJ.PRJ_END_DATE, PORT.TIER1_NAME, PORT.TIER2_NAME, PORT.TIER3_NAME, MAX(A.FIS_WK_END_DATE) AS "FISCAL_WEEK", SUM(A.ABDOL) AS "AAB_DOL", SUM(A.VHDOL) AS "AVH_DOL", SUM(A.ADOL) AS "AA_DOL", SUM(A.DCDOL) AS "ADC_DOL", SUM(A.DCGADOL) AS "ADC_GA_DOL", SUM(A.COM) AS "AM_DOL", SUM(A.FE) AS "AFE_DOL", SUM(A.IE) AS "AIE_DOL", SUM(A.OTHER) AS "AR_DOL", SUM(A.MTSFT) AS "AS_FT", SUM(A.MTSST) AS "AS_ST", SUM(A.ACTST) AS "AL_ST", SUM(A.ACTFT) AS "ALL_FT", MAX(P.SNAPSHOT_DATE) as "SNAP_DATE", P.FINSCN_TYPE, SUM(P.ABDOL) AS "PAB_DOL", SUM(P.VHDOL) AS "PVH_DOL", SUM(P.DCDOL) AS "PDC_DOL", SUM(P.TCI_DOL) AS "PCI_GA_DOL", SUM(P.GADOL) AS "PN_GA_DOL", SUM(P.COM) AS "PN_COM", SUM(P.FEE) AS "PN_FEE", SUM(P.D_IE) AS "PN_MOIE", SUM(P.OTHER) AS "PN_OTHER"
FROM PROJ_TASK_VW PROJ
LEFT JOIN PORTFOLIO_VW PORT
ON PROJ.TASKNO = PORT.TASKNO
LEFT JOIN ACTUAL_VW A
ON PROJ.TASKNO = A.CURR_TASKNO
LEFT JOIN BUDG_DOLL_VW P
ON PROJ.TASKNO = P.CURR_TASKNO
WHERE TO_CHAR(PROJ.PRJ_END_DATE, 'YYYY-MM-DD') > '2018-10-01'
AND PROJ.P_FLAG = 'N'
AND (PROJ.P_TYPE LIKE 'D-%' OR PROJ.P_TYPE LIKE '%MR%' OR PROJ.P_TYPE LIKE '%ID%')
AND (SUBSTR(PROJ.PRJ_NO,3,3) != 'BP' AND SUBSTR(PROJ.PRJ_NO,3,3) != 'PJ')
AND (P.FINSCN_TYPE = 'SR' OR P.FINSCN_TYPE = 'BUG')
AND (A.ABDOL + A.VHDOL + A.ADOL + A.DCDOL + A.DCGADOL + A.COM +
A.FE + A.IE + A.OTHER) <> 0
GROUP BY
PROJ.PRJ_NO,
PROJ.PRJ_NAME,
PROJ.PRJ_BEG_DATE,
PROJ.PRJ_END_DATE,
PORT.TIER1_NAME,
PORT.TIER2_NAME,
PORT.TIER3_NAME,
P.FINSCN_TYPE
我的总体目的是使用左连接（将表“ PROJ”用作父表，其余表根据从“ PROJ”表返回的数据提供子数据）将所有选择字段放入一个表。当查询运行时，它在大约30分钟后超时，是否有更好的方法将此查询写到可以在不超时的情况下构建所需表的位置？
答案 0 :(得分：1)
首先，没有执行计划就无法回答这个问题。您索引了哪些列？但是我注意到了一些事情。
WHERE TO_CHAR(PROJ.PRJ_END_DATE, 'YYYY-MM-DD') > '2018-10-01'
您的列是一个日期，因此您应该将其与日期进行比较，而不是转换为VARCHAR2并对字符串进行不等式。
AND (PROJ.P_TYPE LIKE 'D-%' OR PROJ.P_TYPE LIKE '%MR%' OR PROJ.P_TYPE LIKE '%ID%')
我不确定，但是由于通配符，这些功能可能表现不佳。索引可能会使它们变得更好，但是我不记得通配符搜索如何与索引一起工作。
AND (SUBSTR(PROJ.PRJ_NO,3,3) != 'BP' AND SUBSTR(PROJ.PRJ_NO,3,3) != 'PJ')
这些都不做，因为您的两个SUBSTRs返回的字符串长度为3个字符，并且您将它们与2个字符长的字符串进行比较。
AND (A.ABDOL + A.VHDOL + A.ADOL + A.DCDOL + A.DCGADOL + A.COM + A.FE + A.IE + A.OTHER) <> 0
您实际上是在乎总和吗，还是只是检查这些值中的一个或多个是否非零。如果这些值始终> 0，那么最好将其替换为：
AND ( a.ABDOL > 0 OR A.VHDOL > 0 ...