有条件的多列上的非重复计数

我不知道你的专栏是什么,但你可以随时分组。

SELECT 
  COUNT(1), 
  concat(CITY, ",", COUNTRY) as location 
FROM Customers where CustomerId > 10 
GROUP BY location

基本上,这将计算城市和国家的每个独特组合的1。

SELECT COUNT(
  DISTINCT (CASE WHEN CustomerId > 10 
    THEN CONCAT(CITY,",",COUNTRY) END)
  ) 
FROM Customers;

出现“Error 1:could not prepare statement(1 near“,”:syntax Error),因为THEN子句需要1个不带逗号的参数