Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
270 views
in Technique[技术] by (71.8m points)

php - How to create virtual column using MySQL SELECT?

If I do SELECT a AS b and b is not a column in the table, would query create the "virtual" column?

in fact, I need to incorporate some virtual column into the query and process some information into the query so I can use it with each item later on.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Something like:

SELECT id, email, IF(active = 1, 'enabled', 'disabled') AS account_status FROM users

This allows you to make operations and show it as columns.

EDIT:

you can also use joins and show operations as columns:

SELECT u.id, e.email, IF(c.id IS NULL, 'no selected', c.name) AS country
FROM users u LEFT JOIN countries c ON u.country_id = c.id

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

1.4m articles

1.4m replys

5 comments

57.0k users

...