如何計算兩列中具有相同值的行並僅返回count <N（SQL）的行？

Question

關於這個問題： How to count rows that have the same values in two columns (SQL)?

有沒有辦法返回只有在計數< 3行？

+-----+-----+-----+ 
| A | B |count| 
+=====+=====+=====+ 
| 1 | 3 | 2 | 
+-----+-----+-----+ 
| 4 | 2 | 1 | 
+-----+-----+-----+ 

Answer 1

的HAVING條款

SELECT ... 
FROM ... 
WHERE ... 
GROUP BY whatever 
HAVING count(*) <3 

Answer 2

只需添加條件HAVING子句中

SELECT colName, COUNT(*) 
FROM tableName 
GROUP BY colName 
HAVING COUNT(*) < 3