How do I use a variable to specify the column name in a update statement

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SQL-Server-2005

My code is

SQL

declare @ColName varchar(20)
declare @sql nvarchar(1000)


set @ColName='Days1'

set @sql='update Table1 set'+' '+ @ColName+'=P'
print @sql
EXEC sp_executesql @sql

when I run this then out put comes

update Table1 set Days1=P
Msg 207, Level 16, State 1, Line 1
Invalid column name 'P'.

Posted 6-May-15 21:08pm

Member 7909353

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Abhinav S · Accepted Answer · 2015-05-06T21:18:00

Solution 1

You are missing quotes for the string update.
set @sql='update Table1 set'+' '+ @ColName+'=''P'''

Posted 6-May-15 21:18pm

Abhinav S

Comments

Member 7909353 7-May-15 4:50am

declare @ColName varchar(20)
declare @sql nvarchar(1000)
DECLARE @sitename nvarchar(30)
DECLARE @userId nvarchar(10)
DECLARE @cn nvarchar(70)
set @cn=(select ContractorName from Table1);
set @userid=1
set @ColName='Days1'
set @sql='update Table1 set'+' '+ @ColName+'=''P'''+' where UserId='+@userId
It is right
but when I concate

set @sql='update Table1 set'+' '+ @ColName+'=''P'''+' where UserId='+@userId+' and ContractorName='+@cn

print @sql
EXEC sp_executesql @sql

update Table1 set Days1='P' where UserId=1 and ContractorName=a
Msg 207, Level 16, State 1, Line 1
Invalid column name 'a'.

Abhinav S 7-May-15 4:55am

Same problem. You need quotes outside strings.

Member 7909353 7-May-15 7:41am

I have tried but no solution

Member 7909353 8-May-15 2:05am

yes it is solved
set @sql='update Table1 set'+' '+ @ColName+'=''P'''+' where UserId='+@userId+' and ContractorName='+''''+@cn+''''