完成以下功能;
-- 1.查询客户的英文名,要求以小写字母显示
select lower(ename)ename
from user
-- 2.将客户的中文名和英文名连接成一个字符串展示
select concat(name,',',if(ename is null,'',ename))
from user
-- 3.查找1992年出生的客户的交易记录信息
select transinfo.*
from user,card,transinfo
where user.userId=card.userId and card.cardNo=transinfo.cardNo and substring(user.personId,7,4)=1992
-- 4.按姓氏统计客户信息:展示每个姓氏有多少张银行卡
select left(name,1),count(card.cardNo)
from user,card
where user.userId=card.userId
GROUP BY left(name,1)
-- 5.查找姓名是两个汉字的客户信息
select *
from user
where char_length(name)=2
-- 6.展示客户的出生日期,以【1998-02-23】格式展示
select name,concat(substring(user.personId,7,4),'-',substring(user.personId,11,2),'-',substring(user.personId,13,2))
from user