[英]In Mysql how to get records which for the same foreign key has all values showed up in a list for another col
在MySql DB中,我有一個deviceBindingInfo表,其中包含userId和deviceType,如何選擇已綁定所有deviceTypes {A,B,C}的所有userId
以下解決方案正確嗎? 還是有更好的解決方案?
SELECT userId
FROM (SELECT userId, deviceType
FROM deviceBindingInfo
WHERE deviceType IN (A, B, C)
GROUP BY userId, deviceType) AS TempTable
GROUP BY userId
HAVING COUNT(userId) >= 3;
您不應該使用沒有聚合功能的組來刪除內部select中的重復項,您可以為此使用DISTINCT並獲得正確的計數,而應使用count(deviceType)(在這種情況下,結果相同。匹配A,B,C)
SELECT userId
FROM (
SELECT
distinct userId
, deviceType
FROM deviceBindingInfo
WHERE deviceType IN (A, B, C)
) AS TempTable
GROUP BY userId HAVING COUNT(deviceType) >= 3;
或者您可以使用count(distinct deviceType)進行子查詢
SELECT
userId
FROM deviceBindingInfo
WHERE deviceType IN (A, B, C)
group by userId
HAVING COUNT(deviceType) >= 3;
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