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sqlsql-serversql-server-2008sql-server-2008-r2sql-server-2012

How to add dynamic column to an existing table


I have 2 tables 1st table contains following columns,

 id code    Name
 1  c1  chk1
 2  c2  chk2
 3  c3  chk3

2nd table contains following columns,

id,Name,Chk1,chk2,Chk3

i have to add the column 'Chk4' into table2 if table1 is updated with value '4,'c4','ch4' dynamically.How to write procedure to perform this?

i've tried the following procedure but its not working fine.

         create proc Add_Check
          as 
          begin
          declare @Column varchar(50)
          declare @query varchar(255)
          declare @query1 varchar(255)
          set @Column= (select top 1 QUOTENAME(Name)
            from table1 where id=(Select MAX id) from table1))
          if exists(select 1 from table1
         where Name=@Column) 
         begin
         set @query = 'alter table table2 add ' + @Column + ' Varchar (50)'
         set @query1 = 'alter table table2 add ' + @Column + '_CompletedDate Varchar (50)'
         exec(@query)
         end
         end

Solution

  • use this query as procedure.

    CREATE PROC ADD_CHECK
    AS 
    BEGIN
        DECLARE @COLUMN VARCHAR(50)
        DECLARE @QUERY VARCHAR(255)
        DECLARE @QUERY1 VARCHAR(255)
    
        SET @COLUMN= (SELECT TOP 1 NAME FROM TABLE1 WHERE ID=(SELECT MAX (ID)     FROM TABLE1))
    
        IF EXISTS(SELECT 1 FROM TABLE1 WHERE NAME=@COLUMN) 
        BEGIN
            SET @QUERY = 'ALTER TABLE TABLE2 ADD ' + @COLUMN + ' VARCHAR (50)'
            SET @QUERY1 = 'ALTER TABLE TABLE2 ADD ' + @COLUMN + '_COMPLETEDDATE VARCHAR     (50)'
            EXEC(@QUERY)
        END
    END