getting error on mysql query that I use UNION - mysql

Question

My SQL query
SELECT DISTINCT a.*,categories_2625729.title AS category_title,categories_2625729.id AS category,c.id as cid, c.title, '' as `introtext`, 'com_hpj_content.ad' as content_type, '' as banner, '' as `fulltext`, '' as sheettext, c.publish_up, c.publish_down, c.price, c.advertiser_id, c.seller_id, c.sold, c.soldupdated,0 AS is_favorite
FROM `jos_hpj_content_item` AS a
LEFT JOIN jos_categories AS categories_2625729 ON categories_2625729.id = a.category
LEFT JOIN jos_hpj_content_item_ad AS cff ON cff.id = a.ref_id AND a.content_type = 'com_hpj_content.ad'
LEFT JOIN jos_fields_values AS fields_values_min_maxyear ON fields_values_min_maxyear.item_id = a.ref_id AND fields_values_min_maxyear.field_id=8
LEFT JOIN jos_fields_values AS fields_values_min_max_2mileage ON fields_values_min_max_2mileage.item_id = a.ref_id AND fields_values_min_max_2mileage.field_id=10
LEFT JOIN jos_hpj_content_item_ad c ON c.`id` = a.`ref_id` AND a.`content_type`='com_hpj_content.ad'
WHERE a.state = 1 AND (`c`.title LIKE '%22%' OR c.`introtext` LIKE '%22%' OR a.synonym LIKE '%22%') AND a.content_type IN ('com_hpj_content.ad') AND a.ref_id IN (53,307,353,354,572,644,717,934,978,1056,1086,1128,1149,1199,1276,1294,1314,1324,1347,1351,1396,1411,1462,1470,1513,1537,1740,1741,1836,1861,1916,1988,1989,2005,2006,2124,2158,2266,2267,2268,2277,2511,2575,2577,2582,2585,2587,2654,2815,2894,2906,2975,3021,3179,3194,3219,3224,3239,0) AND a.state = 1
UNION (SELECT name FROM jos_users WHERE name LIKE '%22%')
I'm getting error
#1222 - The used SELECT statements have a different number of columns
If I remove UNION the sql query return result but if I keep UNION the error return
I'm trying to search the number in different tables in c.title or in name from jos_user and return the result

Answer 1

As #danblack points out in comments, the error
#1222 - The used SELECT statements have a different number of columns
is saying that there's a different number of columns on the two SELECT statement. In
SELECT DISTINCT a.*,
categories_2625729.title AS category_title,
categories_2625729.id AS category,c.id as cid,
c.title,
'' as `introtext`,
'com_hpj_content.ad' as content_type,
'' as banner,
'' as `fulltext`,
'' as sheettext,
c.publish_up,
c.publish_down,
c.price,
c.advertiser_id,
c.seller_id,
c.sold,
c.soldupdated,0 AS is_favorite
FROM ...
..you're select a lot more columns than in this
SELECT name
FROM ...
The number of columns of those two SQL statements have to match in order for UNION to be able to add the results of the second query to the result of the first.
So this will work:
SELECT DISTINCT c.title
FROM ...
UNION
SELECT name
FROM ...
because now both individual SELECT statements return just one column.