我正在尝试在名为#LIST的表中更新名为Specialty的列。我需要从3个不同的表中提取信息，因为1表中的专业是NULL。我更喜欢使用#Segment表中的专业，如果那是NULL，那么我想使用#SUBMARKET表中的专业，如果那是NULL，我想使用#MARKET表中的专业。
当我运行以下查询时，它不会更新任何行。我不想使用超过1个Update语句。我该怎么办？
UPDATE #LIST
SET Specialty = CASE WHEN (l.Segment__c is not NULL) THEN s.Specialty
WHEN (l.Segment__c is NULL) THEN b.Specialty
WHEN (l.Submarket__c is NULL) THEN m.Specialty
ELSE s.Specialty
END
FROM #LIST l
join #MARKET m on m.Market = l.Market__c
join #SUBMARKET b on b.Submarket = l.Submarket__c
join #Segment s on s.Segment = l.Segment__c
答案 0 :(得分：1)
您需要使用Array
(
[listen] => Array
(
[445] => 445
[9091] => 9091
[3306] => 3306
[587] => 587
[11211] => 11211
[139] => 139
[80] => 80
[3312] => 3312
[51413] => 51413
[22] => 22
[631] => 631
[25] => 25
[443] => 443
[993] => 993
[143] => 143
)
[syn_recv] => Array
(
[80] => 80
)
[time_wait] => Array
(
[80] => 80
[51413] => 51413
)
[established] => Array
(
[22] => 22
[9091] => 9091
[80] => 80
[3306] => 3306
)
[fin_wait2] => Array
(
[80] => 80
)
)
中的表别名。另外，我认为您需要UPDATE：
left join否则，UPDATE l
SET Specialty = CASE WHEN (l.Segment__c is not NULL) THEN s.Specialty
WHEN (l.Segment__c is NULL) THEN b.Specialty
WHEN (l.Submarket__c is NULL) THEN m.Specialty
ELSE s.Specialty
END
FROM #LIST l
left join #MARKET m on m.Market = l.Market__c
left join #SUBMARKET b on b.Submarket = l.Submarket__c
left #Segment s on s.Segment = l.Segment__c;
值将过滤掉行，因为它们在连接中不匹配。