Question

When I imported a table in SQL it suggested real datatype, now I would like to change all columns to double type…

Is there any script to automatically do this in SQL Managment Studio

My table is 500 columns:

`After doing` EXECUTE sp_help traS

Col Type  Comp len Prec Scale   Nullable TrimTrailing Fixed Collation
------------------------------------------------------------------------------- 
x1  real    no  4   24      NULL    yes (n/a)   (n/a)   NULL
x2  real    no  4   24      NULL    yes (n/a)   (n/a)   NULL
x3  real    no  4   24      NULL    yes (n/a)   (n/a)   NULL
x4  real    no  4   24      NULL    yes (n/a)   (n/a)   NULL
...
x500 real   no  4   24      NULL    yes (n/a)   (n/a)   NULL

Answer 1

The following code will place a list of columns into a temporary table called @cols, loop through that table, generate an alter table alter column statement, and execute it for each column.

If you need to exclude columns, you should include those in the NOT IN predicate of the select from information_schema.columns.

declare @cols table (i int identity, colname varchar(100))
insert into @cols
select column_name
from information_schema.COLUMNS
where TABLE_NAME = 'yourtable'
and COLUMN_NAME not in ('exclude1', 'exclude2')

declare @i int, @maxi int
select @i = 1, @maxi = MAX(i) from @cols

declare @sql nvarchar(max)

while(@i <= @maxi)
begin
    select @sql = 'alter table yourtable alter column ' + colname + ' decimal(18,4) NULL'
    from @cols
    where i = @i

    exec sp_executesql @sql

    select @i = @i + 1
end