美好的一天!我目前在更新数据库方面遇到了麻烦。我在c#.net中编码并使用SQL服务器。
我的问题是我尝试有条件地更新多个列。这是我的代码:
"Update Eureka Set Milestone1 = Case When Milestone1 = '" + araw.Text + "' then Milestone_status = '" + m1 + "' End, Milestone2 = When Milestone2 = '" + araw.Text + "' then Milestone_status = '" + m2 + "' End, Milestone3 = When Milestone3 = '" + araw.Text + "' Then Milestone_status = '" + m3 + "' End, Milestone4 = When Milestone4 = '" + araw.Text + "' Then Milestone_status = '" + m4 + "' End, Milestone5 = When Milestone5 = '" + araw.Text + "' Then Milestone_status = '" + m5 + "' End Where Eureka_id = '" + eid.Text + "'"
如果Milestone1等于今天的日期(araw.text),那么里程碑状态将会改变。如果没有,则里程碑_状态不会被更改。那么里程碑2到里程碑5也是如此。
我的代码是SQL语句无法正常工作。任何帮助将不胜感激。
答案 0 :(得分:1)
将它从C#中取出并将其视为单独的SQL语句,并且为了简单起见只考虑里程碑1,您的SQL必须是这样的:
UPDATE Eureka
SET milestone_status =
CASE WHEN milestone1 = @todays_date then @m1
ELSE milestone_status
END
即。如果milestone1是今天的日期,则将milestone_status设置为@ m1,否则将其设置为自身(即不要更改它)。
SQL文档有几个关于CASE语法使用的好例子,为清晰起见,可能值得一看:https://msdn.microsoft.com/en-us/library/ms181765.aspx
希望有所帮助
答案 1 :(得分:1)
尝试;
Update Eureka
Set Milestone_status =
Case
When Milestone1 = @araw_Text then @m1
when Milestone2 = @araw_Text then @m2
when Milestone3 = @araw_Text then @m3
when Milestone4 = @araw_Text then @m4
when Milestone5 = @araw_Text then @m5
else Milestone_status
end
Where Eureka_id = @eid_Text
这将更新
如果Milestone_status
,m1
Milestone1 = araw.Text
Milestone_status
如果m2
,Milestone2 = araw.Text
Milestone_status
m3
Milestone3 = araw.Text
Milestone_status
<?php comment_form(); ?>
,如果<?php comment_form(array('title_reply' => 'Comment with image' )); ?>
....
如果没有满足条件,则func fetchWithPredicate(entityName: String, argumentArray: [AnyObject]) -> [NSManagedObject] {
let fetchRequest = NSFetchRequest(entityName: entityName)
fetchRequest.predicate = NSPredicate(format: "%K == %@", argumentArray: argumentArray)
do {
return try self.managedContext.executeFetchRequest(fetchRequest) as! [NSManagedObject]
} catch {
let fetchError = error as NSError
print(fetchError)
return [NSManagedObject]()
}
}
将不会被修改
答案 2 :(得分:0)
您的CASE语句是蠕虫语法:
Update Eureka
Set Milestone1 = Case When Milestone1 = 'araw.Text' then Milestone_status = 'm1' End
, Milestone2 = When Milestone2 = 'araw.Text' then Milestone_status = 'm2' End
, Milestone3 = When Milestone3 = 'araw.Text' Then Milestone_status = 'm3' End
, Milestone4 = When Milestone4 = 'araw.Text' Then Milestone_status = 'm4' End
, Milestone5 = When Milestone5 = 'araw.Text' Then Milestone_status = 'm5' End
Where Eureka_id = 'eid.Text'
正确的语法必须像
CASE expression
WHEN value_1 THEN result_1
WHEN value_2 THEN result_2
...
WHEN value_n THEN result_n
ELSE result
END
在您的情况下,您可以使用嵌套CASE检查每个里程碑(Milestone1,Milestone2,..)
"Update Eureka
set Milestone_status = case when Milestone1 = '" + araw.Text + "' then '" + m1 + "' else
case when Milestone2 = '" + araw.Text + "' then '" + m2 + "' else
case when Milestone3 = '" + araw.Text + "' then '" + m3 + "' else
case when Milestone4 = '" + araw.Text + "' then '" + m4 + "' else
case when Milestone5 = '" + araw.Text + "' then '" + m5 + "' else Milestone_status end
end
end
end
end
Where Eureka_id = '" + eid.Text + "'"