有谁能告诉我这个语句的性能上的问题！

[Lin2000y]

能告诉我这个语句的效率上的问题
SELECT CASE WHEN AD.SPDM IS NULL
THEN AC.SPDM ELSE AD.SPDM END AS SPDM,
CASE WHEN AD.GG1MC IS NULL
THEN AC.GG1MC ELSE AD.GG1MC END GG1MC,
CASE WHEN AD.GG2MC IS NULL
THEN AC.GG2MC ELSE AD.GG2MC END AS GG2MC,
AD.SL_S AS [订货(C)], AC.SL_S AS [出货(C)]
FROM (SELECT VW_PHJRD.SPDM, SHANGPIN.SPMC, GUIGE1.GGMC AS GG1MC,
GUIGE2.GGMC AS GG2MC, SUM(VW_PHJRD.SL) AS SL_S
FROM VW_PHJRD, SHANGPIN, CANGKU, GUIGE1, GUIGE2
WHERE VW_PHJRD.SPDM = SHANGPIN.SPDM AND
VW_PHJRD.DM1 = CANGKU.CKDM AND
VW_PHJRD.GG1DM = GUIGE1.GGDM AND
VW_PHJRD.GG2DM = GUIGE2.GGDM AND CANGKU.XZDM = '1' AND
CANGKU.YGDM = 'C'
GROUP BY VW_PHJRD.SPDM, SHANGPIN.SPMC, VW_PHJRD.GG1DM,
GUIGE1.GGMC, VW_PHJRD.GG2DM, GUIGE2.GGMC)
AD FULL OUTER JOIN
(SELECT VW_SDPHMX.SPDM, SHANGPIN.SPMC,
GUIGE1.GGMC AS GG1MC, GUIGE2.GGMC AS GG2MC,
SUM(VW_SDPHMX.SL) AS SL_S
FROM VW_SDPHMX, SHANGPIN, CANGKU AS CANGKU1, CANGKU,
GUIGE1, GUIGE2
WHERE VW_SDPHMX.SPDM = SHANGPIN.SPDM AND
VW_SDPHMX.DM1 = CANGKU1.CKDM AND
VW_SDPHMX.DM2 = CANGKU.CKDM AND
VW_SDPHMX.GG1DM = GUIGE1.GGDM AND
VW_SDPHMX.GG2DM = GUIGE2.GGDM AND
CANGKU1.XZDM = '1' AND CANGKU1.YGDM = 'C' AND CANGKU.XZDM = '0'
GROUP BY VW_SDPHMX.SPDM, SHANGPIN.SPMC, VW_SDPHMX.GG1DM,
GUIGE1.GGMC, VW_SDPHMX.GG2DM, GUIGE2.GGMC) AC ON
AD.SPDM = AC.SPDM AND AD.GG1MC = AC.GG1MC AND
AD.GG2MC = AC.GG2MC

[Lin2000y]

如果我再做多一个类似这样的查询要怎么解决？
select ...
from (select ... from
((select .. from A) T1
full outter join
(select .. from A2)T2 on ....)B1
full outter join
(select ... from
((select .. from A) T1
full outter join
(select .. from A2)T2 on ....)B2
on ....)C1
再如此类推下去我应该怎么解决？

[伍子V5]

有些长哈，建议用临时表以及有针对性地建索引

[pengdali]

FULL OUTER JOIN

肯定底。

[zjcxc]

复制到查询分析器中,按"CTRL+K",显示执行计划,然后执行一下,就知道了.

[Lin2000y]

没人告诉我吗？帮帮忙吧

[Lin2000y]

拜托了各位大爷，本人一定高分相送。
我想知道这个这个语句应该怎么改好？

[Lin2000y]

拜托了各位大爷，本人一定高分相送。
我想知道这个这个语句应该怎么改好？

[changechange]

up

[szocean]

hao , guanzhu.

[shaken]

在sql server上这样执行，好像会导致内存溢出，你必须打上最新补丁才行！