SQLite table with AS SELECT - sql

Question

I have a table called flights which has all information related to flights and I have a table called users.
I want to create a new table called orders, in this table I wanted to add user name from the user table and certain flight information from the flight table.
The thing is I also want to have a column in my order table called orderID.
My question is how do I add a column in a as select query

Answer 1

SELECT *, an_expression AS another_column FROM the_table_or_subquery .... ;
an_expression is that, an expression that results in a single value
the_table_or_subquery and another_column are descriptive rather than actual, change accordingly.
the new column could be first e.g. SELECT an_expression AS another_column,* FROM the_table_or_subquery;
Could you please give an example like to better understand
Considering that you have provided scant details then here are examples of creating a new table and inserting some data from wherever and other data from another table (flights) :-
DROP TABLE IF EXISTS flights;
DROP TABLE IF EXISTS users;
DROP TABLE IF EXISTS `order`;
DROP TABLE IF EXISTS other_order_table;
CREATE TABLE IF NOT EXISTS flights (
id INTEGER PRIMARY KEY,
flight_info TEXT
)
;
CREATE TABLE IF NOT EXISTS users (
userid INTEGER PRIMARY KEY,
user_name TEXT UNIQUE,
user_email TEXT UNIQUE
)
;
INSERT OR IGNORE INTO flights (flight_info)
VALUES
('Flight1'),
('Flight2'),
('Flight3')
;
INSERT OR IGNORE INTO users (user_name,user_email)
VALUES
('Fred','fred#email'),
('Mary','mary#email'),
('Jane','jane#email')
;
DROP TABLE IF EXISTS `order`;
/* >>>>>>>>>> NOT A GOOD IDEAD <<<<<<<<<< due to
A table created using CREATE TABLE AS has no PRIMARY KEY and no constraints of any kind.
The default value of each column is NULL.
The default collation sequence for each column of the new table is BINARY.
*/
CREATE TABLE IF NOT EXISTS `order` /* NOTE ORDER is a keyword so has to be enclosed - better to not call it order */
AS SELECT *,null AS orderid /* The new column BUT see above, value will be null*/
FROM flights;
SELECT * FROM `order`;
/* BETTER as can specify column attributes
however must insert elsewhere
*/
CREATE TABLE IF NOT EXISTS other_order_table (
orderid INTEGER PRIMARY KEY,
order_added TEXT DEFAULT CURRENT_TIMESTAMP,
flight_id,
flight_info
)
;
/*
EXAMPLE 1
uses defaults for columns
in the case of orderid as it's an alias of the rowid then autogenerated id
in the case of order_added the current date and time in YYYY-MM-DD hh:mm:ss format
*/
INSERT INTO other_order_table (flight_id,flight_info) SELECT * FROM flights;
SELECT * FROM other_order_table;
DELETE FROM other_order_table;
/* EXAMPLE 2 */
INSERT INTO other_order_table
SELECT
/* a random id will bne inserted into the first column (orderid) */
abs(random()),
/* a random date up to 999 days in the past */
datetime('now','-'||CAST(abs(random()) % 1000 AS INTEGER)||' days'),
/* all the columnd from the flights tables */
*
FROM flights
;
SELECT * FROM other_order_table;
/* Cleanup Ennvironment*/
DROP TABLE IF EXISTS flights;
DROP TABLE IF EXISTS users;
DROP TABLE IF EXISTS `order`;
DROP TABLE IF EXISTS other_order_table;
The 3 results are :-
2 columns from the flights table + new orderID column set to null
WARNING see commentary above re column attributes being stripped
the orderId is generated
the order_added is generated due to default being CURRENT_TIMESTAMP
both the new columns orderid and order_added use expressions that return a random suitable value.