How can I prefix all column names in a T-SQL function?
I have a table T with 2 columns C1 and C2
I want a function that returns T but after prefixing all column names with "PREFIX_".
The prefix is a dynamic string passed to the function.
It is possible?
I want something like
SELECT C1 AS @prefix 开发者_如何学C+ 'C1',
C2 AS @prefix + 'C2'
FROM T
This will do it even when you don't know the columns already.
declare @prefix varchar(20)
declare @sqltext nvarchar(500)
set @prefix = 'prefix_'
declare @columnnames varchar(500)
select @columnnames = coalesce(@columnnames, '')+',' +column_name + ' '+ @prefix+column_name
from INFORMATION_SCHEMA.COLUMNS a where table_name = 't' and table_schema = 'dbo'
set @sqltext = 'select '+stuff(@columnnames,1,1,char(0))+' from t'
exec(@sqltext)
As its for a known number of columns you can construct the SQL string with the alias and exec()
it;
declare @prefix varchar(32) = 'prefix_'
declare @sql nvarchar(1024)
set @sql = 'select C1 as [' + @prefix + 'C1], C2 as [' + @prefix + 'C2] from T'
exec(@sql)
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