[英]mysql row to column with group_concat and count?
我有2个表,用户和以下。 table follow有一个名为status的列。 我想计算每个用户按状态分组的次数。
下面的查询返回每个用户的每种状态类型的记录。
SELECT users.name as user_name, f.status, count(f.id)
FROM users
JOIN application_follows f ON f.user_id = users.id
GROUP BY users.id, f.status
ORDER BY users.id
返回类似于:
user_name status count
mike new 10
mike old 5
tom new 8
tom old 9
但我想要一些更友好的东西:
user_name new old
mike 10 5
tom 8 9
尝试使用group_concat并计数但没有工作。 有线索吗?
SELECT user_name,
MAX(CASE WHEN status = 'new' THEN totalFollowers ELSE NULL END) `NEW`,
MAX(CASE WHEN status = 'old' THEN totalFollowers ELSE NULL END) `OLD`
FROM
(
SELECT users.name as user_name,
f.status,
count(f.id) totalFollowers
FROM users
LEFT JOIN application_follows f
ON f.user_id = users.id
GROUP BY users.id, f.status
) derivedTable
GROUP BY user_name
或者(
不确定这一个 )
SELECT users.name as user_name, MAX(CASE WHEN f.status = 'new' THEN count(f.id) ELSE NULL END) `NEW`, MAX(CASE WHEN f.status = 'old' THEN count(f.id) ELSE NULL END) `OLD` FROM users LEFT JOIN application_follows f ON f.user_id = users.id GROUP BY users.id, f.status
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