大家好，我是mysql查询的初学者。我在 mysql 中使用此查询时遇到一个错误:
SELECT enquiry.business_id ,enquiry_count ,b.`business_name`,c.`id`
FROM `consumer_guide_enquiry_company` enquiry
INNER JOIN `businesses` b ON `enquiry`.`business_id`=b.`business_id`
INNER JOIN `consumer_guide_company` c ON c.`business_id`=b.`business_id`
WHERE CASE
WHEN enquiry.`business_id`
IN (
SELECT b.business_id
FROM `businesses` b,`consumer_guide_company` c
WHERE b.`business_id`=c.`business_id` AND c.`consumer_guide_id`=1)
THEN enquiry_count=COUNT(enquiry.enquiry_id)
ELSE enquiry_count=0
END
GROUP BY enquiry.business_id
显示错误:“字段列表”中未知列“enquiry_count”
感谢您的帮助
最佳答案
尝试这样
SELECT enquiry.business_id ,case when enquiry_count is NULL then 0
else enquiry_count end 'enquiry_count' ,b.`business_name`,c.`id`
FROM `consumer_guide_enquiry_company` enquiry
INNER JOIN `businesses` b ON `enquiry`.`business_id`=b.`business_id`
INNER JOIN `consumer_guide_company` c ON c.`business_id`=b.`business_id`
LEFT JOIN (SELECT b.business_id,count(*) as enquiry_count FROM `businesses`
b,`consumer_guide_company` c WHERE b.`business_id`=c.`business_id` AND
c.`consumer_guide_id`=1 group by b.business_id) as tt
ON enquiry.`business_id`=tt.b.business_id
GROUP BY enquiry.business_id
关于mysql - 我的 SQL 查询 : Error :Unknown column in field list when using CASE WHEN in WHERE clause，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22853588/