如何优化查询语句
有如下查询语句
SELECT "WM001"."KBH",
"WM001"."BZ",
"WM001"."BS_YKSQDH",
(SELECT MAX("WM064"."YKDH") FROM "WM064" WHERE "WM064"."YKSQDH"="WM001"."BS_YKSQDH"),
(SELECT MAX("WM064"."SHRQ") FROM "WM064" WHERE "WM064"."YKSQDH"="WM001"."BS_YKSQDH"),
FROM "WM001"
WHERE "WM001"."BS_KB_STATUS"<5 ;
如何优化使得查询速度加快
[解决办法]
子查询数据不大的话，应该不慢！
要么就重新设计表结构了！
[解决办法]
SELECT "WM001"."KBH",
"WM001"."BZ",
"WM001"."BS_YKSQDH",
MAX("WM064"."YKDH"),
MAX("WM064"."SHRQ"),
FROM "WM001", "WM064"
WHERE "WM001"."BS_KB_STATUS" <5 AND "WM064"."YKSQDH"="WM001"."BS_YKSQDH" AND
"WM064"."YKSQDH"="WM001"."BS_YKSQDH"
GROUP BY "WM001"."KBH",
"WM001"."BZ",
"WM001"."BS_YKSQDH"
