How Can I use Alias in Where - php

Question

This is my code but it's not working:
$select = $db->select()
->from(array('p' => 'products'), 'p.product_id')
->columns(array('x' => new Zend_Db_Expr('(SELECT...)'
)))
->where('x = ?', 'value');
// Alternatively use columns('p.product_name')
How can I retrieve x and compere it in where clause?
This is the actual query:
SELECT `abstract_submission`.*,
(SELECT GROUP_CONCAT(CONCAT(user.firstName, " ", user.lastName) SEPARATOR ",")
FROM mamba_event.abstract_submission_reviewer reviewer INNER JOIN
mamba_account.account_user user ON user.id = reviewer.userId
WHERE reviewer.submissionId = mamba_event.abstract_submission.id AND
user.isEnabled = 1)
AS `reviewers`,
(SELECT GROUP_CONCAT(CONCAT(author.firstName, " ", author.lastName) SEPARATOR ",")
FROM mamba_event.abstract_author author INNER JOIN
mamba_event.abstract_submission_author map ON author.id = map.authorId
WHERE map.submissionId = mamba_event.abstract_submission.id)
AS `allAuthors`,
(SELECT COUNT(`abstract_paper`.`id`) FROM `mamba_event`.`abstract_paper`
WHERE `abstract_paper`.`submissionId` = `abstract_submission`.`id`)
AS `numPapers`,
(SELECT `paperNumber` FROM `mamba_event`.`abstract_paper`
WHERE `abstract_paper`.`submissionId` = `abstract_submission`.`id` AND
`abstract_paper`.`currentStatus` = 3 LIMIT 1)
AS `acceptedPaperNumber`,
(SELECT IF ((COUNT(1) > 0), 'Paper has been uploaded','None') AS hasUploadedPaper
FROM `mamba_event`.`abstract_paper` paper
WHERE paper.submissionId = `mamba_event`.`abstract_submission`.`id`)
AS `hasUploadedPaper`,
(SELECT GROUP_CONCAT(CONCAT(user.firstName, " ", user.lastName) SEPARATOR ",")
FROM `mamba_event`.`abstract_submission_reviewer` reviewer INNER JOIN
`mamba_account`.`account_user` user ON user.id = reviewer.userId
WHERE reviewer.submissionId = `mamba_event`.`abstract_submission`.`id`
AND reviewer.hasConflictOfInterest = 1
AND user.isEnabled = 1)
AS `reviewersWithConflict`,
(SELECT AVG(`score`) FROM `mamba_event`.`abstract_submission_score`
WHERE `submissionId` = `abstract_submission`.`id`)
AS `averageScore`,
(SELECT AVG(`score`) FROM `mamba_event`.`abstract_paper_score`, `mamba_event`.`abstract_paper`
WHERE `abstract_paper_score`.`paperId` = `abstract_paper`.`id`
AND `abstract_paper`.`submissionId` = `abstract_submission`.`id`
AND (`abstract_paper`.`currentStatus` = 1
OR `abstract_paper`.`currentStatus` = 3))
AS `averagePaperScore`,
(SELECT AVG(`score`*`scoreWeight`) FROM `mamba_event`.`abstract_submission_score` INNER JOIN
`mamba_event`.`abstract_request_criteria` ON `criteriaId` = `abstract_request_criteria`.`id`
WHERE `submissionId` = `abstract_submission`.`id`)
AS `averageWeightedScore`,
(SELECT AVG(`score`*`scoreWeight`) FROM `mamba_event`.`abstract_paper_score` JOIN
`mamba_event`.`abstract_paper` INNER JOIN
`mamba_event`.`abstract_request_criteria` ON
`criteriaId` = `abstract_request_criteria`.`id`
WHERE `abstract_paper_score`.`paperId` = `abstract_paper`.`id`
AND `abstract_paper`.`submissionId` = `abstract_submission`.`id`
AND (`abstract_paper`.`currentStatus` = 1
OR `abstract_paper`.`currentStatus` = 3))
AS `averageWeightedPaperScore`, `author`.`email`
AS `authorEmail`, `author`.`salutation`
AS `authorTitle`, `author`.`firstName`
AS `authorFirstName`, `author`.`lastName`
AS `authorLastName`, `author`.`organisation`
AS `authorOrganisation`, `author`.`position`
AS `authorPosition`, `author`.`department`
AS `authorDepartment`, `author`.`phone`
AS `authorPhone`, `author`.`fax`
AS `authorFax`, `address`.`line1`
AS `addressLine1`, `address`.`line2`
AS `addressLine2`, `address`.`line3`
AS `addressLine3`, `address`.`line4`
AS `addressLine4`, `address`.`city`
AS `addressCity`, `address`.`stateCode`
AS `addressStateCode`, `address`.`countryCode`
AS `addressCountryCode`, `address`.`postalCode`
AS `addressPostalCode`, `author`.`biography`
AS `authorBiography`, `request`.`title`
AS `request`, `request`.`blindReview`, `request`.`hasCustomTypes`, `file`.`content_type`, `file`.`original_filename` AS `filename`, `author`.`speakerId`,
(SELECT GROUP_CONCAT(
CONCAT('',ifnull(author.firstName,'-'),' ',
ifnull(author.lastName,'-'),'
(',ifnull(author.organisation,'-'),',
',ifnull(author.authorCountryCode,'-'),')')
SEPARATOR ",")
FROM `mamba_event`.`abstract_author` author LEFT JOIN
`mamba_event`.`abstract_submission_author` sa
ON sa.authorId = author.id
WHERE sa.submissionId = `abstract_submission`.`id`)
AS `authorDetails`,
(SELECT GROUP_CONCAT(`field`.`fieldValue`)
FROM `mamba_abstract`.`author_field_value_varchar` `field`
WHERE `field`.`fieldId` = '2185'
AND `field`.`authorId` = `abstract_submission`.`presenterId`)
AS `field2185`,
(SELECT GROUP_CONCAT(`field`.`fieldValue`)
FROM `mamba_abstract`.`author_field_value_varchar` `field`
WHERE `field`.`fieldId` = '2335'
AND `field`.`fieldValue` = 'BSCS'
AND `field`.`authorId` = `abstract_submission`.`presenterId`)
AS `field2335`,
(SELECT GROUP_CONCAT(`field`.`fieldValue`)
FROM `mamba_abstract`.`author_field_value_varchar` `field`
WHERE `field`.`fieldId` = '2336'
AND `field`.`authorId` = `abstract_submission`.`presenterId`)
AS `field2336` FROM `mamba_event`.`abstract_submission`
INNER JOIN `mamba_event`.`abstract_request` AS `request` ON requestId = request.id
LEFT JOIN `mamba_account`.`account_file` AS `file` ON fileId = file.id
INNER JOIN `mamba_event`.`abstract_author` AS `author` ON `presenterId` = `author`.`id`
LEFT JOIN `mamba_general`.`address` ON `author`.`addressId` = `address`.`id` WHERE ((`abstract_submission`.`isEnabled` = '1') AND (`abstract_submission`.`eventId` = '1893')) AND (`field2335` LIKE "%BSCS%") ORDER BY `request` asc LIMIT 15

Answer 1

You could do it with HAVING, like Muhammad Zeeshan said.
$select = $db->select()
->from(array('p' => 'products'), 'p.product_id')
->columns(array('x' => new Zend_Db_Expr('(SELECT...)')))
->having('x = ?', 'value');