Question

我有一个包含数据和结构的表：

+-----------+-----------+-----------+-----------+
| member_id | bank_name |  bank_ac  | ac_holder |
+-----------+-----------+-----------+-----------+
|        14 |           |   012-000 |           |
|        14 |           |   012-001 |      Andy |
|        14 |   CR Bank |   012-002 |     Jacky |
+-----------+-----------+-----------+-----------+

我需要的是选择一个条目，所有列都填充第一个非空值。为：

+-----------+-----------+-----------+-----------+
| member_id | bank_name |  bank_ac  | ac_holder |
+-----------+-----------+-----------+-----------+
|        14 |   CR Bank |   012-000 |     Andy  |
+-----------+-----------+-----------+-----------+

我不知道如何开始。有人能给我建议吗？

ps：空字段不是NULL，它们是空字符串。架构提供here

Answer 1

您可以使用某些聚合

select member_id,
min(bank_name) bank_name,
min(bank_ac) bank_ac,
min(ac_holder) ac_holder
from demo
group by member_id

DEMO

如果您的数据包含空值，例如''（注意null与''不相同），那么您可以将case子句放在聚合函数中以跳过这些类型的值

<击>

select member_id,
min(case when bank_name is not null and bank_name <> '' then bank_name end) bank_name,
min(case when bank_ac is not null and bank_ac <> '' then bank_ac end) bank_ac,
min(case when ac_holder is not null and ac_holder <> '' then ac_holder end) ac_holder
from demo
group by member_id

<击> DEMO

您的问题的另一种解决方法

select member_id,
substring_index(group_concat(case when bank_name is not null and bank_name <> '' then bank_name end order by your_auto_increment_col asc) ,',',1) bank_name,
substring_index(group_concat(case when bank_ac is not null and bank_ac <> '' then bank_ac end  order by your_auto_increment_col asc) ,',',1) bank_ac,
substring_index(group_concat(case when ac_holder is not null and ac_holder <> '' then ac_holder end  order by your_auto_increment_col asc) ,',',1) ac_holder
from demo
group by member_id

DEMO

Mysql将许多行合并为一个非空值

1 个答案: