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语句为:
SELECT "yd_ddxx"."lpmc",
CONVERT( integer, sum(yd_ddxx.lpgs) )
FROM "yd_ddxx"
WHERE "yd_ddxx"."ddbh" in ( SELECT "yd_ddxx"."ddbh" FROM "yd_ddxx" GROUP BY "yd_ddxx"."ddbh" HAVING(count(*)) > 1 )
GROUP BY "yd_ddxx"."lpmc"
;
执行速度很慢,执行计划为:
( Plan [ Total Cost Estimate: 40.54128 ]
( WorkTable
( HashGroupBy
( TableScan yd_ddxx[ EXISTS( SubQ 1 ) ] )
)
)
)
( SubQ 1 [ Total Cost Estimate: 40.54128 ]
( Filter [ expr() > 1 : 25% Guess ]
( HashGroupBy
( TableScan yd_ddxx[ yd_ddxx.ddbh = expr( yd_ddxx.ddbh ) : 5% Guess ] )
)
)
)
我看不懂,表结构为:
yd_ddxx: ddbh,lpbh,lpmc,lpgs |
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