按最大和顺序分组

Question

在这样的表格中：

code        code1   code2   code3   code4
FILA841201  123456  481201  654987  NULL
NULL        123456  481201  1234    NULL
NULL        123456  481201  789014  324324

我只需要得到一行，今天使用这些查询

CREATE TABLE tmp2 (SELECT max(code) as code, code1, max(code2) as code2, max(code3) as code3, max(code4) as code4 FROM tmp1 WHERE code1 IS NOT NULL group by code1);

CREATE TABLE tmp3 (SELECT max(code) as code, max(code1) as code1, code2, max(code3) as code3, max(code4) as code4 FROM tmp1 WHERE code2 IS NOT NULL group by code2);

ecc...为所有列循环

我的问题是，如果一列有不同的值，我必须让位于第一列被填满的那一行。

在此示例中，我必须输出“654987”而不是最大值 (789014)。

我应该得到的结果

code        code1   code2   code3   code4
FILA841201  123456  481201  654987  324324

感谢您的关注

Answer 1

假设您有一列指定行的顺序，您可以使用相关子查询来做到这一点：

select (select code from tmp1 where code is not null order by id limit 1) as code,
       (select code1 from tmp1 where code1 is not null order by id limit 1) as code1,
       (select code2 from tmp1 where code2 is not null order by id limit 1) as code2,
       (select code3 from tmp1 where code3 is not null order by id limit 1) as code3,
       (select code4 from tmp1 where code4 is not null order by id limit 1) as code4