菜鸟写法：
SELECT * from Groups WHERE `Name` = 'tyj天赢居'
SELECT * from GroupEasemob WHERE `groupId` = 72
大神写法：
SELECT * from Groups left join GroupEasemob on Groups.groupId = GroupEasemob.groupId WHERE `Name` = 'tyj天赢居'
SELECT * FROM User where UserName = 'CM-8117622'
SELECT * from Groups left join GroupEasemob on Groups.groupId = GroupEasemob.groupId WHERE `Name` LIKE '%猎枪'
select * from GroupUserRelation where userid=8117622 and groupid=117 and expiredTime>now()
SELECT
easemobId
FROM
GroupUserRelation
WHERE
userid =(
SELECT
userid
FROM
User
WHERE
UserName = 'CM-8008316'
)
AND groupid =(
SELECT
Groups.GroupId
FROM
Groups
LEFT JOIN GroupEasemob ON Groups.groupId = GroupEasemob.groupId
WHERE
`Name` = '木头玩股'
LIMIT 1
)
AND expiredTime > now()
