计算mysql中唯一数据的出现次数

Question

所以我知道如果我想要计算具有相同城市名称的条目数，我将使用以下代码：

SELECT *, COUNT(*) AS count
FROM location
GROUP BY city
ORDER BY count
DESC

如果我想计算具有相同城市名称和州名的条目数量，我该如何去做呢？

citynameA，stateNameB =具有相同cityname和statename的条目数

Answer 1

您可以将多个字段与group by一起使用，例如

SELECT city, state, COUNT(*) AS count
FROM location
GROUP BY city, state
ORDER BY count
DESC