我是一个写sql的新手，所以先谢谢大家的帮助。我在mysql数据库中有一个表（table1），视图是这样的。
+-----+----------+------------+
| id | key | value |
+-----+----------+------------+
| 1 | name | Bob |
| 1 | location | ABC |
| 1 | date | xxxx-xx-xx |
| 2 | name | Jim |
| 2 | location | MID |
| 2 | date | |
| 3 | name | |
| 3 | location | |
| 3 | date | |
| 4 | name | Sue |
| 4 | location | DFW |
| 4 | date | xxxx-xx-xx |
| 5 | name | Sue |
| 5 | location | |
| 5 | date | xxxx-xx-xx |
| 6 | name | Bob |
| 6 | location | GRE |
| 6 | date | xxxx-xx-xx |
| 7 | name | |
| 7 | location | |
| 7 | date | |
+-----+----------+------------+
我创建了一个视图，我基本上反转（枢轴）的行到列这样。
+-----+-------+----------+------------+
| id | name | location | date |
+-----+-------+----------+------------+
| 1 | Bob | ABC | xxxx-xx-xx |
| 2 | Jim | MID | |
| 3 | | | |
| 4 | Sue | DFW | xxxx-xx-xx |
| 5 | Sue | | xxxx-xx-xx |
| 6 | Bob | GRE | xxxx-xx-xx |
| 7 | | | |
| 8 | Bob | DFW | xxxx-xx-xx |
| 9 | | | |
| 10 | Joe | DFW | xxxx-xx-xx |
| 11 | | | |
| 12 | | | |
| 13 | | | |
| 14 | Jim | SUS | xxxx-xx-xx |
+-----+-------+----------+------------+
下面是我做这个的代码。
select c.`id`, max(ifnull(c.name,NULL)) as name, max(ifnull(c.location,NULL)) as location, max(ifnull(c.date,NULL)) as date from (
select `id`,
case when `key` = 'name' then value end as name,
case when `key` = 'location' then value end as location,
case when `key` = 'date' then value end as date
from `table1`
WHERE value != ''
) c group by `id`
我需要从视图中过滤掉那些名字，地点，日期为NULL或空白的行。我可以通过在视图中添加的 WHERE value != ''但我如何过滤掉其他的东西？WHERE value IS NOT NULL 似乎没有帮助。