Suppose that you want to change the note column a NOT NULL column with a maximum of 100 characters.įirst, show the column list of the vehicles table: DESCRIBE vehicles It’s a good practice to view the attributes of a column before modifying it. Here is the basic syntax for modifying a column in a table: ALTER TABLE table_name This statement shows the new structure of the vehicles table: DESCRIBE vehicles Ĭode language: SQL (Structured Query Language) ( sql ) MySQL ALTER TABLE – Modify columns 1) Modify a column To add multiple columns to a table, you use the following form of the ALTER TALE ADD statement: ALTER TABLE table_nameįor example, this statement adds two columns color and note to the vehicles table: ALTER TABLE vehicles This statement shows the column list of the vehicles table: DESCRIBE vehicles Īs shown clearly from the output, the column model has been added to the vehicles table. The following example uses the ALTER TABLE ADD statement to add a column at the end of the vehicles table: ALTER TABLE vehicles If you omit this clause, the column is appended at the end of the column list of the table. You can add a column after an existing column ( ATER column_name) or as the first column ( FIRST). FIRST | AFTER column_name specify the position of the new column in the table.column_definition– specify the datatype, maximum size, and column constraint of the new column.new_column_name – specify the name of the new column.table_name – specify the name of the table that you want to add a new column or columns after the ALTER TABLE keywords.To add a column to a table, you use the ALTER TABLE ADD syntax: ALTER TABLE table_nameĬode language: SQL (Structured Query Language) ( sql ) The ALTER TABLE ADD statement allows you to add one or more columns to a table. Let’s create a table named vehicles for the demonstration: CREATE TABLE vehicles (Ĭode language: SQL (Structured Query Language) ( sql ) MySQL ALTER TABLE – Add columns to a table Summary: in this tutorial, you will learn how to use the MySQL ALTER TABLE statement to add a column, alter a column, rename a column, drop a column and rename a table.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |