将多行合并为一行MySQL，并在同一查询中将值从一个字段拆分为两个

Question

I'm kind of new to MySQL but I've managed to find the individual solutions to two things I was trying to do, now I just need help combining them.

I have a database with a two tables: Users and user_profile. I have managed to create a query that combines data from both tables into a single table with the following:

select t1.id,
  t1.name,
  max(case when t2.`profile_key` = 'profile.address1' then t2.profile_value end) address,
  max(case when t2.`profile_key` = 'profile.city' then t2.profile_value end) city,
  max(case when t2.`profile_key` = 'profile.postal_code' then t2.profile_value end) postal_code,
  max(case when t2.`profile_key` = 'profile.phone' then t2.profile_value end) phone
from users t1
left join user_profiles t2
  on t1.id = t2.user_id
group by t1.id, t1.name

I would also like to split the "name" column into "first name" and "last name" so that I can sort by last name. I can accomplish that with this:

SELECT IF(
        LOCATE(' ', `name`) > 0,
        SUBSTRING(`name`, 1, LOCATE(' ', `name`) - 1),
        `name`
    ) AS memberfirst,
    IF(
        LOCATE(' ', `name`) > 0,
        SUBSTRING(`name`, LOCATE(' ', `name`) + 1),
        NULL
    ) AS memberlast
FROM `users`;

Is there a way to combine these quires into one?

Answer 1

UNION SELECT，row1_name，row2_name，FROM tbl_name应该可以解决问题，不记得语法是否正确，但查询是union :)

Answer 2

I think I understand that you want the first and last name instead of just the name, so try this:

SELECT t1.id,
IF(
    LOCATE(' ', t1.name) > 0,
    SUBSTRING(t1.name, 1, LOCATE(' ', t1.name) - 1),
    t1.name
    ) AS memberfirst,
    IF(
    LOCATE(' ', t1.name) > 0,
    SUBSTRING(t1.name, LOCATE(' ', t1.name) + 1),
    NULL
    ) AS memberlast , 
  MAX(CASE WHEN t2.`profile_key` = 'profile.address1' THEN t2.profile_value END) address,
  MAX(CASE WHEN t2.`profile_key` = 'profile.city' THEN t2.profile_value END) city,
  MAX(CASE WHEN t2.`profile_key` = 'profile.postal_code' THEN t2.profile_value END) postal_code,
  MAX(CASE WHEN t2.`profile_key` = 'profile.phone' THEN t2.profile_value END) phone
FROM users t1
LEFT JOIN user_profiles t2
  ON t1.id = t2.user_id
GROUP BY t1.id, t1.name