I'm trying to compile this in my mind.. i have a table with firstname and lastname fields and i have a string like "Bob Jones" or "Bob Michael Jones" and several others.
the thing is, i have for example Bob in firstname, and Michael Jones in lastname
so i'm trying to
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast
FROM users
WHERE firstlast = "Bob Michael Jones"
but it says unknown column "firstlast".. can anyone help please ?
The aliases you give are for the output of the query - they are not available within the query itself.
You can either repeat the expression:
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast
FROM users
WHERE CONCAT(firstname, ' ', lastname) = "Bob Michael Jones"
or wrap the query
SELECT * FROM (
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast
FROM users) base
WHERE firstLast = "Bob Michael Jones"
Try this:
SELECT *
FROM (
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast
FROM users
) a
WHERE firstlast = "Bob Michael Jones"
SELECT needefield, CONCAT(firstname, ' ',lastname) as firstlast
FROM users
WHERE CONCAT(firstname, ' ', lastname) = "Bob Michael Jones"
Use CONCAT_WS().
SELECT CONCAT_WS(' ',firstname,lastname) as firstlast FROM users
WHERE firstlast = "Bob Michael Jones";
The first argument is the separator for the rest of the arguments.
There is an alternative to repeating the CONCAT
expression or using subqueries. You can make use of the HAVING
clause, which recognizes column aliases.
SELECT
neededfield, CONCAT(firstname, ' ', lastname) AS firstlast
FROM
users
HAVING firstlast = "Bob Michael Jones"
Here is a working SQL Fiddle .
Try:
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast
FROM users
WHERE CONCAT(firstname, ' ', lastname) = "Bob Michael Jones"
Your alias firstlast is not available in the where clause of the query unless you do the query as a sub-select.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.