Unknown column where clause - mysql

Question

I have following DQL query
SELECT
ps.id,
MAX(ps.dueDate) as due_date,
u.firstName as first_name,
u.lastName as last_name,
u.email,
IDENTITY(ps.loanApplication) as loan_application_id,
DATE_DIFF(MAX(ps.dueDate), CURRENT_DATE()) as diff
FROM
Loan\Entity\PaymentSchedule ps
LEFT JOIN
ps.paymentType pt
LEFT JOIN
ps.loanApplication la
LEFT JOIN
la.status s
LEFT JOIN
la.user u
WHERE
pt.slug != :paymentSlug AND s.keyIdentifier = :status AND diff = 14
GROUP BY
ps.loanApplication
Which translates to following SQL query
SELECT
p0_.id AS id_0,
MAX(p0_.due_date) AS sclr_1,
u1_.first_name AS first_name_2,
u1_.last_name AS last_name_3,
u1_.email AS email_4,
p0_.loan_application_id AS sclr_5,
DATEDIFF(MAX(p0_.due_date), CURRENT_DATE) AS sclr_6
FROM
payment_schedule p0_
LEFT JOIN
payment_type p2_ ON p0_.payment_type_id = p2_.id
LEFT JOIN
loan_application l3_ ON p0_.loan_application_id = l3_.id
LEFT JOIN
loan_application_status l4_ ON l3_.loan_application_status_id = l4_.id
LEFT JOIN
user u1_ ON l3_.user_id = u1_.id
WHERE
p2_.slug <> ? AND l4_.key_identifier = ? AND sclr_6 = 14
GROUP BY
p0_.loan_application_id
This gives me following error
======================================================================
PDOException
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'sclr_6' in 'where clause'
----------------------------------------------------------------------
When i replace WHERE condition
WHERE pt.slug != :paymentSlug AND s.keyIdentifier = :status AND diff = 14
With
WHERE pt.slug != :paymentSlug AND s.keyIdentifier = :status
It works perfectly and displays me correct record, i also tried following WHERE condition
WHERE pt.slug != :paymentSlug AND s.keyIdentifier = :status AND DATE_DIFF(MAX(ps.dueDate), CURRENT_DATE()) = :days_diff
WHERE pt.slug != :paymentSlug AND s.keyIdentifier = :status HAVING (DATE_DIFF(MAX(ps.dueDate), CURRENT_DATE())) = :days_diff
Above WHERE does not work as well, what am i missing here ?
Thanks.

Answer 1

If you want to use the alias in your WHERE clause you need a sub-select.
select *
from
(SELECT
p0_.id AS id_0,
MAX(p0_.due_date) AS sclr_1,
u1_.first_name AS first_name_2,
u1_.last_name AS last_name_3,
u1_.email AS email_4,
p0_.loan_application_id AS sclr_5,
DATEDIFF(MAX(p0_.due_date), CURRENT_DATE) AS sclr_6
FROM
payment_schedule p0_
LEFT JOIN
payment_type p2_ ON p0_.payment_type_id = p2_.id
LEFT JOIN
loan_application l3_ ON p0_.loan_application_id = l3_.id
LEFT JOIN
loan_application_status l4_ ON l3_.loan_application_status_id = l4_.id
LEFT JOIN
user u1_ ON l3_.user_id = u1_.id
) A
WHERE
slug <> ? AND key_identifier = ? AND sclr_6 = 14
This is how query is logically processed
FROM clause
WHERE clause
SELECT clause
GROUP BY clause
HAVING clause
ORDER BY clause
Since Where comes before Select you cannot use alias name in Where clause

Answer 2

You cannot use an alias (on the final result fields) in the WHERE clause; however, at least with MySQL, you may use a HAVING clause without needing a GROUP BY.

Answer 3

The expression you are using is the result of an aggregation. Replace add a having clause so the query looks like;
SELECT . . .
WHERE p2_.slug <> ? AND l4_.key_identifier = ?
GROUP BY p0_.loan_application_id
HAVING sclr_6 = 14
Note that date_diff() is not a function in MySQL. You intend datediff().