How to add the column and than update the column in sql server using procedure - sql

Question

i have created the table called test_exam
create table test_exam(id int,age int)
than i want through procedure add column called name and update it value.
i have made the procedure
create procedure [dbo].[abcd1] #tablename sysname
as
begin
declare #query nvarchar(4000)
declare #name_test varchar(20)
set #query = N'select top 10 * from transorg_DW.dbo.'+#tablename
print #query
alter table test_exam add name varchar(20);
update test_exam set name='shyam' where id=1;
exec sp_executesql
end
its through an error
invalid column name.
how to rectify this error?

Answer 1

You should call it dynamically and in separate, I think, it will for the column at the compile time so it is displaying error. For now you can do the following
DECLARE #sql NVARCHAR(500)
SET #sql = ' alter table purchase add stat int'
EXEC sp_executesql #sql
SET #sql = ' update purchase set stat=0'
EXEC sp_executesql #sql
Note: Please check the column existence if you would need to call multiple times

Answer 2

When you add any column to existing table then allow null or provide some default value.
And also prevent the DDL command from being executed more then once, otherwise it will throw error on next execution.
And for update its throw error because name column didn't exist while creating the proc. Update statement must as dynamic query.
create procedure [dbo].[abcd1] #tablename sysname
as
begin
declare #query nvarchar(4000)
declare #name_test varchar(20)
set #query = N'select top 10 * from transorg_DW.dbo.'+#tablename
print #query
if not exists(select * from sys.columns c join sys.tables t on c.object_id=t.object_id
where t.name='test_exam' and c.name='name')
begin
--new column added must be as null value or default value
alter table test_exam
add name varchar(20) null;
end
declare #query1 nvarchar(4000)
set #query1='update test_exam set name=''shyam'' where id=1';
exec (#query1)
exec sp_executesql
end
Enjoy hope this will help.