concat(s1,s2,s3...)字符连接
upper(s)转大写
substr(s,i,length),i为第i个字符,i>=1
select cust_id,cust_name,
upper(concat(substr(cust_contact,1,2),substr(cust_city,1,3)))
as user_login from Customers;
concat(s1,s2,s3...)字符连接
upper(s)转大写
substr(s,i,length),i为第i个字符,i>=1
select cust_id,cust_name,
upper(concat(substr(cust_contact,1,2),substr(cust_city,1,3)))
as user_login from Customers;