Insert into table with column same values as auto increment column ( computed column )

Question

Say I have a table with "column1" (Primary Key, Auto Increment) and "column2".

How can insert into the table with column2 will have the same values as column1 which is auto increment column?

Answer 1

You can create a table with a Calculated column that it's value is equal to column1. Each time you insert a row into your table column1 will be inserted as identity and column2 will be euqal to that.

MySql :

CREATE TABLE myTable 
  (column1 int NOT NULL AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(50) NOT NULL,
  column2 int);
INSERT INTO myTable (name) VALUES('John Doe')
UPDATE mytable SET column2 = column1;

Best ways for MySql : Calculated column or trigger that I refer you to these answers : Calculated Column MySql , Insert, then update, Create before insert trigger

You can add other columns like name.

Sql Server :

CREATE TABLE myTable 
  (column1 int identity (1,1) NOT NULL,
  name nvarchar(100),
  column2 as column1);

INSERT INTO myTable (name) VALUES('John Doe')