SQL - 如何創建透視表和現有表的視圖

Question

我在用戶創建的表單上有一個用於動態字段的表：

表格的格式如下：

ID  | FIELD NAME 
-------------------
1   | Gross Gallons

為了與其他表形成連接，我需要創建一個如下所示的視圖

ID_1 
------------
Gross Gallons

任何幫助，將不勝感激

謝謝

Answer 1

這是一種制作動態字段的簡單方法。

給定表：

mysql> select * from dyna_field;

+------+---------------+
| id   | field_name    |
+------+---------------+
|    1 | Gross Gallons |
|    2 | Net Gallons   |
|    3 | Total         |
+------+---------------+

進行動態查詢：

select 
  group_concat(concat('(case when id = ', id, ' then field_name else "" end) as ID_', id, ' ')) into @sql_case
from dyna_field 
join(SELECT @sql_case:='') c;

set @sql_case = concat('select ', @sql_case, ', 1 as uid from dyna_field;');

prepare statement FROM @sql;

execute statement;

+---------------+-------------+-------+-----+
| ID_1          | ID_2        | ID_3  | uid |
+---------------+-------------+-------+-----+
| Gross Gallons |             |       |   1 |
|               | Net Gallons |       |   1 |
|               |             | Total |   1 |
+---------------+-------------+-------+-----+