您好所有我有如下表 -LEFT OUTER JOIN不工作
tr_resource作爲資源 -
Resourceid name
135021 ABC
tr_charac作爲chlev -
characid name
1 CH1
2 CH2
tr_characvalue作爲cvlev -
characvalueid characid stringvalue
cv1 1 XX
cv2 2 YY
cv3 2 zz
tr_resourcecharac作爲rchlev -
resourceid characvalueid
135021 cv2
當我運行下面的查詢 -
select
res.name,
cvlev.stringvalue
from tr_resource res
left outer join tr_resourcecharac rchlev on res.RESOURCEID = rchlev.RESOURCEID
inner join tr_characvalue cvlev on rchlev.CHARACVALUEID = cvlev.CHARACVALUEID
inner join tr_charac chlev on chlev.CHARACID = cvlev.CHARACID and chlev.NAME = 'CH2'
where res.resourceid=135021
我得到的答案 -
name stringvalue
ABC YY
但是當我運行下面的查詢,我沒有得到任何答案 -
select
res.name,
cvlev.stringvalue
from tr_resource res
left outer join tr_resourcecharac rchlev on res.RESOURCEID = rchlev.RESOURCEID
inner join tr_characvalue cvlev on rchlev.CHARACVALUEID = cvlev.CHARACVALUEID
inner join tr_charac chlev on chlev.CHARACID = cvlev.CHARACID and chlev.NAME = 'CH1'
where res.resourceid=135021
我想獲得回答r as -
name stringvalue
ABC null
您能否幫忙?
嗨Raniendu感謝您的回覆,但用左外連接代替內連接沒有工作 – anidesh