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| Total_cost | float(9,4) | YES | | NULL | |

| Field | Type | Null | Key | Default | Extra | Query OK, 0 rows affected (0.34 sec) mysql> desc mydbops_lab_test_1 In this example i will calculate the balance amount to the test table.So i created a new table with virtual column.īalance_amount float(12,6) GENERATED ALWAYS AS (Total_cost - Expensive),.

| id | firstname | lastname | full_name | email_id |Īdding a virtual column on existing table : mysql> ALTER TABLE v_column ADD full_name char(41) GENERATED ALWAYS AS (concat(firstname,' ',lastname)) VIRTUAL NOT NULL We need to test the full name column, so populate a few row into the contacts table. | email_id | varchar(25) | YES | | NULL | | | full_name | char(41) | YES | | NULL | VIRTUAL GENERATED | | lastname | varchar(20) | YES | | NULL | | | firstname | varchar(20) | YES | | NULL | | | id | int(11) | NO | PRI | NULL | auto_increment | | Field | Type | Null| Key | Default | Extra | (id int(11) NOT NULL AUTO_INCREMENT primary key,įull_name char(41) GENERATED ALWAYS AS (concat(firstname,' ',lastname)),Įmail_id varchar(25)) Query OK, 0 rows affected (0.40 sec) mysql> desc mydbops_lab_test Use Cases:įor example we have a mydbops_lab_test table structure as below, mysql> create table mydbops_lab_test STORED – The column values are evaluated and stored when rows are inserted or updated. VIRTUAL – The column values are not stored, but these are evaluated when rows are read. GENERATED ALWAYS – It indicates that the column is a generated column. => Alter table table_name add column column_name generated always as column_name virtual Īlter table contacts add column generated always as mydbops_test virtual / stored. Virtual columns are one of the top features in MySQL 5.7,they can store a value that is derived from one or several other fields in the same table in a new field.