如何選擇主查詢次數爲子查詢

Question

我想要得到的是在主查詢選擇成我目前正在執行的子查詢

查詢記錄數：

SELECT cat_id,category_name,seo_name,(SELECT count(category_name) FROM ccs_coupons WHERE (category_name LIKE category_name OR website_name LIKE category_name OR description LIKE LIKE category_name OR url_desc LIKE category_name)) FROM `ccs_coupons` WHERE category_name like 'a%' GROUP BY category_name ORDER BY category_name ASC LIMIT $page,$config 

Answer 1

你可以只使用兩個表，而不是相關子查詢之間的連接：

SELECT c.id, 
    u.display_name, 
    c.comments_count 
FROM users u 
LEFT JOIN 
(
    SELECT COUNT(*) comments_count, author_id 
    FROM cms_comments 
    GROUP BY author_id 
) c 
    ON c.author_id = u.id 
WHERE c.comments_count > 150; 

編輯，根據您的更新，你仍然應該能夠使用這樣的事情：

SELECT c1.cat_id, 
    c1.category_name, 
    c1.seo_name, 
    c2.CountCategoryName 
FROM `ccs_coupons` c1 
LEFT JOIN 
(
    SELECT count(category_name) CountCategoryName, category_name, 
     website_name, description, url_desc 
    FROM ccs_coupons 
    GROUP BY category_name 
) c2 
    on c2.category_name LIKE c1.category_name 
    or c2.website_name LIKE c1.category_name 
    or c2.description LIKE c1.category_name 
    or c2.url_desc LIKE c1.category_name 
WHERE c1.category_name like 'a%' 
ORDER BY c1.category_name ASC 
LIMIT $page,$config; 

甚至使用：

SELECT c1.cat_id, 
    c1.category_name, 
    c1.seo_name, 
    count(c2.category_name) 
FROM `ccs_coupons` c1 
INNER JOIN ccs_coupons c2 
    on c2.category_name LIKE c1.category_name 
    or c2.website_name LIKE c1.category_name 
    or c2.description LIKE c1.category_name 
    or c2.url_desc LIKE c1.category_name 
WHERE c1.category_name like 'a%' 
GROUP BY c1.category_name 
ORDER BY c1.category_name ASC 
LIMIT $page,$config; 

Answer 2

你不能把HAVING子句外部查詢，因爲它是不是彙總查詢。試試這個：

SELECT users.id, 
     users.display_name, 
     COUNT(*) AS comments_count 
    FROM users 
    INNER JOIN cms_comments 
    ON users.id = cms_comments.author_id 
GROUP BY users.id, users.display_name 
HAVING COUNT(*) > 150;