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[英]MySQL and PHP: Getting a SUM from a row in column A based on a DATE from column A joined by an ID in column B?
[英]MySQL: Getting value from column A that corresponds to MIN from column B
我有下表:
step_id hospital_id step_number step_name
17 8 4 First Step
18 8 1 Second Step
19 8 2 Third Step
20 8 3 Finance Approval
我想做的是獲取對應於最小步數的step_id。 因此,在上面的示例中,我正在尋找step_id 18。
在查看了許多帖子之后,我一直嘗試以下變化,但無濟於事:
SELECT `step_id`
FROM `progress_steps`
WHERE `hospital_id` = 8
GROUP BY `step_id`
HAVING MIN(`step_number`)
似乎對其他人有用,但是上面返回了示例中的所有行,而我嘗試給我的其他變體僅給了step_id 17。
您可以使用ORDER BY
和LIMIT
SELECT *
FROM tableName
WHERE hospital_id = 8
ORDER BY step_number ASC
LIMIT 1
或者,如果要獲取具有相同最低step_number
多行,請使用子查詢:
SELECT *
FROM tableName
WHERE step_Number =
(
SELECT step_Number
FROM tableName
WHERE hospital_id = 8
ORDER BY step_number ASC
LIMIT 1
)
試試這個
SELECT `step_id`
FROM `progress_steps`
WHERE `hospital_id` = 8
Order BY `step_id`
LIMIT 1
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