mysql - SELECT 中的 COUNT() 未产生所需的输出

Question

我有 2 个表:

美国各州城市:

还有usstatescentroids:

SELECT state,COUNT(*) AS  count  FROM usStateCities  GROUP BY state

给出每个州的城市数量

SELECT *
FROM (SELECT state, COUNT(*)  AS count FROM  usstatecities ) AS a,
usstatescentroids b
WHERE a.state = b.state
GROUP BY state

只给出美国的一个州和城市总数 我想找到每个州的城市数量和每个州的质心坐标(经度，纬度)。

更正我已将状态更改为状态。我剪切并粘贴了旧语句。

Answer 1

SELECT a.state, a.count, b.lon, b.lat 
FROM (SELECT State, COUNT(*) AS count FROM usStateCities GROUP BY State) a
LEFT JOIN usstatescentroids b ON b.state = a.State