我創建了一個表
CREATE TABLE visits (
user_id int,
event_date timestamp
);
INSERT INTO visits (user_id, event_date)
VALUES
(1, '2021-12-22 12:12:00'),
(1, '2021-12-23 12:12:05'),
(1, '2021-12-24 12:13:00'),
(1, '2021-12-24 12:14:00'),
(1, '2022-03-10 12:14:00'),
(1, '2022-03-11 12:14:00'),
(2, '2021-12-23 12:12:00'),
(1, '2022-03-12 12:14:00'),
(2, '2021-12-23 13:12:00'),
(1, '2022-03-13 12:14:00'),
(1, '2022-03-14 12:14:00'),
(3, '2021-12-25 12:12:00'),
(1, '2022-03-15 12:14:00'),
(1, '2022-03-20 12:14:00'),
(1, '2022-03-21 12:14:00'),
(1, '2022-03-23 12:14:00'),
(1, '2022-03-24 12:14:00'),
(1, '2022-03-25 12:14:00'),
(3, '2021-12-30 12:12:00'),
(3, '2021-12-31 12:12:00'),
(3, '2021-12-31 12:12:00'),
(4, '2022-03-21 12:12:00'),
(4, '2022-03-22 12:12:00'),
(4, '2022-03-23 12:12:00'),
(4, '2022-03-24 12:12:00');
然后我嘗試用
select
user_id,
distinct cast(event_date as date) as event_date
from visits;
我得到
ERROR 1064 (42000) at line 111: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'distinct cast(event_date as date) as event_date
來自第 3 行的訪問
我做錯了什么？
uj5u.com熱心網友回復：
您應該將關鍵字 distinct 放在首位：
select distinct cast(event_date as date) as event_date, user_id
from visits;
要么
select distinct user_id, cast(event_date as date) as event_date
from visits;
這是一個演示
uj5u.com熱心網友回復：
您可以使用GROUP BY. （該欄COUNT是可選的）
SELECT
count(*) "number",
user_id,
DATE(event_date) "event date"
FROM visits
GROUP BY
user_id,
DATE(event_date)
ORDER BY
user_id,
DATE(event_date);
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