我不懂sql,有个问题要问你。我需要在sql中创建一个计数,我尝试过了,但没有结果。所以我有一张桌子:
Event Participant Participant count
Test 123 3
Test 123 3
Test 456 1
Test 123 3
我需要为参与者创建一个计数:参与者123有3个参与,参与者456有1个参与。请帮帮我。Thx提前这么多
你尝试了什么?您需要某种聚合函数,使用groupby语句。例如
SELECT
participant,
count(*) AS countofparticipations,
sum(participantcount) AS sumofparticipations
FROM
mytable
GROUP BY
participant
您需要的是mysql 中的"group-by"
SELECT Participant,
count(Participant_count)
FROM tblName
GROUP BY participant;
SELECT Participant,
count(Participant_count) AS participant_count
FROM tblName
GROUP BY participant;