Mysql 在select语句中进行分组
这是我的SQLMysql 在select语句中进行分组,mysql,sql,database,Mysql,Sql,Database,这是我的SQL SELECT c.name AS 'name', COUNT(sc.condition_id) AS 'conditions_count' FROM reviews r, strain_conditions sc LEFT JOIN conditions c ON sc.condition_id = c.id WHERE sc.strain_id = 1 && sc.review_id = r.id && r.moderated = 1 GRO
SELECT c.name AS 'name',
COUNT(sc.condition_id) AS 'conditions_count'
FROM reviews r, strain_conditions sc
LEFT JOIN conditions c ON sc.condition_id = c.id
WHERE sc.strain_id = 1 && sc.review_id = r.id && r.moderated = 1
GROUP BY sc.condition_id
ORDER BY conditions_count DESC
LIMIT 3;
返回
+---------------+------------------+
| name | conditions_count |
+---------------+------------------+
| Fiber Myalgia | 2 |
| Anxiety | 2 |
| ADHD | 1 |
+---------------+------------------+
我需要做的是在名称results上分组,这样我的最终结果就简单了
“纤维肌痛、焦虑、ADHD”您需要嵌套选择,因为
限制应仅适用于子查询
SELECT GROUP_CONCAT(name) AS name
FROM
(
SELECT c.name AS name
FROM reviews r, strain_conditions sc
LEFT JOIN conditions c ON sc.condition_id = c.id
WHERE sc.strain_id = 1 && sc.review_id = r.id && r.moderated = 1
GROUP BY sc.condition_id
ORDER BY conditions_count DESC
LIMIT 3
) AS T1
如果要按降序计数排序,应在组中添加一个ORDER by
SELECT GROUP_CONCAT(name ORDER BY conditions_count DESC) AS name
FROM
(
-- your query here
) AS T1
如果还需要逗号后的空格,请使用分隔符:
SELECT GROUP_CONCAT(name ORDER BY conditions_count DESC SEPARATOR ', ') AS name
FROM
(
-- your query here
) AS T1
有关更多详细信息,请参阅的手册页。将其包装在子查询中。试试这个
SELECT GROUP_CONCAT(f.name) as `name`
FROM
(
SELECT c.name AS 'name',
COUNT(sc.condition_id) AS 'conditions_count'
FROM reviews r, strain_conditions sc
LEFT JOIN conditions c ON sc.condition_id = c.id
WHERE sc.strain_id = 1 && sc.review_id = r.id && r.moderated = 1
GROUP BY sc.condition_id
ORDER BY conditions_count DESC
LIMIT 3
) f
您需要将其放置在子选择中:
SELECT GROUP_CONCAT(name) AS name
FROM
(
SELECT c.name AS 'name',
COUNT(sc.condition_id) AS 'conditions_count'
FROM reviews r, strain_conditions sc
LEFT JOIN conditions c ON sc.condition_id = c.id
WHERE sc.strain_id = 1 && sc.review_id = r.id && r.moderated = 1
GROUP BY sc.condition_id
ORDER BY conditions_count DESC
LIMIT 3
) x
你想让它们以任何特定的顺序出现还是无关紧要?