Changing the data type of an sql column

Question

Good morning.

I have the spine CliTelCel char(10) on the table of Clientes, need to change char(10) for char(11). However this column already exists data, what would be the best way to proceed in this case, without losing the existing data and make the appropriate change?

Thank you.

Answer 1

First of all, have a Backup, this is the guarantee that nothing will be lost.

To change the type or size:

ALTER TABLE Clientes ALTER COLUMN CliTelCel char(11)

Data will not be lost as you just increased column size.

You can also enter some data to complete the column (e.g.:0)

Update  Clientes set CliTelCel= '0'+CliTelCel

Answer 2

alter table Clientes alter column CliTelCel char(11)

Answer 3

whereas the SGBD be it SQL Server you can change the type directly:

ALTER TABLE [tabela] ALTER COLUMN [coluna] char(11);