Question

Declare @count nvarchar(max)

set @count ='select COUNT(*) from '+ @tablename+''

if( @count =0 )
begin 
  print 'fail'
end
else
begin
  print 'success'
end
end

the @count variable is not getting the value 0. it shows the error as

Conversion failed when converting the nvarchar value ‘select COUNT(*) from tablename’ to data type int.

Answer 1

This should work:

DECLARE @SQLString nvarchar(500);
DECLARE @ParmDefinition nvarchar(500);
DECLARE @count int

SET @SQLString = N'SELECT @CountOUT = COUNT(*) FROM ' + @tablename;
SET @ParmDefinition = N'@CountOUT int OUTPUT';

EXECUTE sp_executesql @SQLString, @ParmDefinition, @CountOUT=@count OUTPUT;

SELECT @count;