create table crd_kh(    khm int primary key auto_increment,    khmc varchar(30) -- 客户名);insert crd_kh(khmc) values ("客户1"),("客户2"),("客户3"),("客户4"),("客户5")create table crd_ht(    htbh int primary key auto_increment,    htzt int, -- 交易状态    dkje decimal(20,3), -- 合同总价    khm int REFERENCES crdkh(khm));alter table crd_ht add  dkje decimal(20,3) after htzt-- 已签合同的数量select count(*) from crd_ht where htzt = 1update crd_ht set dkje = 100-- 查询已签合同的客户，合同份数，合同总金额。select COUNT(*) from crd_ht ht     left join crd_kh kh on ht.khm = kh.khm where htzt = 1select khmc as "客户名称",count(*) as "合同数量",sum(dkje) as "合同总价" from crd_kh as kh    left join crd_ht as ht     on ht.khm = kh.khm    where htzt = 1      GROUP BY kh.khmc        select sum(dkje) as "总价" from crd_htinsert crd_ht(htzt,khm) values (1,1),(0,1),(1,1),(0,2),(1,2),(1,3),(0,4),(1,5),(0,1)