Alterando o nome da tabela – ALTER

CREATE TABLE tblAntiga (Codigo INT)

– Insere valores

INSERT INTO tblAntiga VALUES (1)

INSERT INTO tblAntiga VALUES (2)

INSERT INTO tblAntiga VALUES (3)

– Faz uma consulta

SELECT Codigo FROM tblAntiga

– Altera o nome

exec sp_rename ‘tblAntiga’, ‘tblNova’

– Faz uma consulta com o novo nome

SELECT Codigo FROM tblNova

– Elimina a tabela (com o novo nome)

DROP TABLE tblNova

—————————————————————————————————————————————————

A instrução ALTER TABLE

A instrução ALTER TABLE é usado para adicionar, excluir ou modificar colunas em uma tabela existente.

SQL Sintaxe ALTER TABLE

Para adicionar uma coluna em uma tabela, use a seguinte sintaxe:

To delete a column in a table, use the following syntax (notice that some database systems don’t allow deleting a column):

To change the data type of a column in a table, use the following syntax:

SQL ALTER TABLE Example

Look at the “Persons” table:

Now we want to add a column named “DateOfBirth” in the “Persons” table.

We use the following SQL statement:

Notice that the new column, “DateOfBirth”, is of type date and is going to hold a date. The data type specifies what type of data the column can hold. For a complete reference of all the data types available in MS Access, MySQL, and SQL Server, go to our complete Data Types reference .

The “Persons” table will now like this:

Change Data Type Example

Now we want to change the data type of the column named “DateOfBirth” in the “Persons” table.

We use the following SQL statement:

Notice that the “DateOfBirth” column is now of type year and is going to hold a year in a two-digit or four-digit format.

DROP COLUMN Example

Next, we want to delete the column named “DateOfBirth” in the “Persons” table.

We use the following SQL statement:

——————————————————————————————————————————————————

Links úteis:

http://www.1keydata.com/sql/sql-alter-table.html

Tweet