计数列值

Question

表名：user_test_details

我想按照以下结果，

question_id   option_a   option_b   option_c   option_d   option_e
1             0          1          0          0          1
2             2          0          0          0          0
3             0          0          1          0          1
4             0          0          2          0          0

我想要计数，option_a在question_id 1中重复多少次，如果不是则重复0次，如果是，那么根据计数。与其他选项（option_b，option_c，option_d，option_e）相同。更多声明，这里是question_id 4，option_c重复2次，结果，question_id 4，option_c值为2.

Answer 1

使用条件聚合：

SELECT
    question_id,
    SUM(CASE WHEN option_a = 'option_a' THEN 1 ELSE 0 END) AS option_a,
    SUM(CASE WHEN option_b = 'option_b' THEN 1 ELSE 0 END) AS option_b,
    SUM(CASE WHEN option_c = 'option_c' THEN 1 ELSE 0 END) AS option_c,
    SUM(CASE WHEN option_d = 'option_d' THEN 1 ELSE 0 END) AS option_d,
    SUM(CASE WHEN option_e = 'option_e' THEN 1 ELSE 0 END) AS option_e,
FROM user_test_details
GROUP BY question_id

Answer 2

select question_id,count(option_a) as option_a,count(option_b) as option_b,count(option_c) as option_c,count(option_d) as 
option_d,count(option_e) option_e from user_test_details group by question_id

Answer 3

尝试这样的事情。

SELECT DISTINCT question_id, 
    COALESCE(optA.option_a,0) as option_a, 
    COALESCE(optB.option_b,0) as option_b 
FROM user_test_details
LEFT JOIN 
    (
    SELECT question_id, count(option_a) as option_a FROM user_test_details 
    WHERE
    option_a is not null or option_a <> '' group by option_a) 
AS optA
ON user_test_details.question_id = optA.question_id

LEFT JOIN 
    (
    SELECT question_id, count(option_b) as option_b FROM user_test_details 
    WHERE
    option_b is not null or option_b <> '' group by option_b) 
AS optB
ON user_test_details.question_id = optB.question_id

是的，我知道它看起来很脏。