Learn SQL Database Programming

Syntax for creating and altering tables

In order to create a table, you can use the following sample syntax. The items in square brackets are optional:

CREATE TABLE schemaname.tablename (col1name datatype [constraintinfo] [AUTO_INCREMENT],col2name datatype [constraintinfo],...colNname datatype [constraintinfo][PRIMARY KEY (col1name),][UNIQUE KEY uniquekeyname (col1name),]); 

You can alter a table in several different ways, as follows:

• Altering a table to add a column:

ALTER TABLE tablenameADD COLUMN colname datatype [constraintinfo] [AFTER othercolname];

• Altering a table to add multiple columns:

ALTER TABLE tablenameADD COLUMN col1name datatype [constraintinfo] [AFTER othercolname], ADD COLUMN col2name datatype [constraintinfo] [AFTER ...