"or"的迷惑,求教.

[haihuan23]

select * from tj_tjjlb WHERE TJBH  in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301'  AND  tjcs=1

有2403条记录

select * from tj_tjjlb WHERE TJBH  in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301'  AND  tjcs=2

只有1条记录..

select * from tj_tjjlb WHERE TJBH  in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301'  AND tjcs=1 or tjcs=2

有24000多条记录...


请教为什么会这样?

[SQL77]

AND 的优先级大于OR

[haihuan23]

呃.看不见啊
3条SQL分别是:

select * from tj_tjjlb WHERE TJBH in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301' AND tjcs=1


select * from tj_tjjlb WHERE TJBH in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301' AND tjcs=2


select * from tj_tjjlb WHERE TJBH in (select tjbh from tj_tjdjb where tjbh in (select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301' AND tjcs=1 or tjcs=2

[SQL77]

select * from tj_tjjlb WHERE TJBH
in (select tjbh from tj_tjdjb where tjbh in
(select tjbh from tj_tjdjb where dwbh like '0141%') and tjbh<='122140') AND TJXMBH ='0301' AND (tjcs=1 or tjcs=2))

有24000多条记录...


请教为什么会这样?

[haihuan23]

SQL77:

谢谢..加上括号就可以有2404条了...