Question

我有一个条件，MySQL中的字段可以具有相同的值（端口号），但可以代表两个不同的设备，基于主机ID。我有以下内容，但它似乎不起作用：

SELECT s.name AS 'ingester',
    d.dev_used AS 'size',
    Cast(CASE d.namespace_port
        (WHEN 4015 AND d.das_station IN(11,22,23)) THEN 'BPN1'
        (WHEN 4015 AND d.das_station NOT IN(11,22,23)) THEN 'SJC12'
        WHEN 4016 THEN 'SJC17'
        WHEN 4017 THEN 'SJC18'
        WHEN 4018 THEN 'SJC19'
        WHEN 4019 THEN 'SJC5'
        WHEN 4020 THEN 'SJC6'
        WHEN 4021 THEN 'SJC7'
        WHEN 4022 THEN 'SJC8'
        WHEN 4023 THEN 'SJC9'
        WHEN 4024 THEN 'SJC10'
        WHEN 4025 THEN 'SJC11'
        WHEN 4026 THEN 'SJC20'
        WHEN 4027 THEN 'SJC13'
        WHEN 4028 THEN 'SJC14'
        WHEN 4029 THEN 'SJC15'
        WHEN 4030 THEN 'SJC16'
    END AS CHAR) AS namespace,
    Date_format(d.date_attached, '%b-%e-%Y %l:%i %p') AS 'date_attached',
    Date_format(d.replication_started, '%b-%e-%Y %l:%i %p') AS 'date_started',
    Date_format(d.replication_completed, '%b-%e-%Y %l:%i %p') AS 'date_finished',
    Date_format(d.date_detached, '%b-%e-%Y %l:%i %p') AS 'date_detached'
FROM   das.stations s,
       das.device d
WHERE  d.das_station = s.id
AND svcid = "trrq"
ORDER  BY d.date_attached DESC

阅读MYSQL CASE STATEMENT MULTIPLE CONDITIONS，似乎这应该是可能的，但是当我尝试执行查询时，我得到以下内容：

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '4015 AND d.das_station IN(11,22,23)) THEN 'BPN1'
 4015 AND d.das_station NOT IN (1' at line 4

在这样的case语句中是否不能有AND条件？

编辑：似乎粘贴到Mysql中不喜欢查询

mysql> SELECT s.name AS 'ingester',
    ->     d.dev_used AS 'size',
    ->     Cast(CASE d.namespace_port
    ->
Display all 891 possibilities? (y or n)
    ->  (4015 AND d.das_station IN (11,22,23)) THEN 'BPN1'
    ->
Display all 891 possibilities? (y or n)
    ->  (4015 AND d.das_station NOT IN (11,22,23)) THEN 'SJC12'
    ->         WHEN 4016 THEN 'SJC17'
    ->         WHEN 4017 THEN 'SJC18'
    ->         WHEN 4018 THEN 'SJC19'
    ->         WHEN 4019 THEN 'SJC5'
    ->         WHEN 4020 THEN 'SJC6'
    ->         WHEN 4021 THEN 'SJC7'
    ->         WHEN 4022 THEN 'SJC8'
    ->         WHEN 4023 THEN 'SJC9'
    ->         WHEN 4024 THEN 'SJC10'
    ->         WHEN 4025 THEN 'SJC11'
    ->         WHEN 4026 THEN 'SJC20'
    ->         WHEN 4027 THEN 'SJC13'
    ->         WHEN 4028 THEN 'SJC14'
    ->         WHEN 4029 THEN 'SJC15'
    ->         WHEN 4030 THEN 'SJC16'
    ->     END AS CHAR) AS namespace,
    ->     Date_format(d.date_attached, '%b-%e-%Y %l:%i %p') AS 'date_attached',
    ->     Date_format(d.replication_started, '%b-%e-%Y %l:%i %p') AS 'date_started',
    ->     Date_format(d.replication_completed, '%b-%e-%Y %l:%i %p') AS 'date_finished',
    ->     Date_format(d.date_detached, '%b-%e-%Y %l:%i %p') AS 'date_detached'
    -> FROM   das.stations s,
    ->        das.device d
    -> WHERE  d.das_station = s.id
    -> AND svcid = "trrq"
    -> ORDER  BY d.date_attached DESC

如果我删除换行符，它似乎正确粘贴，但仍然不尊重第二个字段：

mysql> SELECT s.name AS 'ingester',    d.das_station,  d.dev_used AS 'size',     Cast(CASE d.namespace_port WHEN (4015 AND d.das_station = 11) THEN 'BPN1' WHEN (4015 AND d.das_station NOT IN(11,22,23)) THEN 'SJC12' WHEN 4016 THEN 'SJC17' WHEN 4017 THEN 'SJC18' WHEN 4018 THEN 'SJC19' WHEN 4019 THEN 'SJC5' WHEN 4020 THEN 'SJC6'  WHEN 4021 THEN 'SJC7' WHEN 4022 THEN 'SJC8'  WHEN 4023 THEN 'SJC9' WHEN 4024 THEN 'SJC10' WHEN 4025 THEN 'SJC11' WHEN 4026 THEN 'SJC20' WHEN 4027 THEN 'SJC13' WHEN 4028 THEN 'SJC14' WHEN 4029 THEN 'SJC15' WHEN 4030 THEN 'SJC16' END AS CHAR) AS namespace,     Date_format(d.date_attached, '%b-%e-%Y %l:%i %p') AS 'date_attached',     Date_format(d.replication_started, '%b-%e-%Y %l:%i %p') AS 'date_started',     Date_format(d.replication_completed, '%b-%e-%Y %l:%i %p') AS 'date_finished',     Date_format(d.date_detached, '%b-%e-%Y %l:%i %p') AS 'date_detached' FROM   das.stations s,        das.device d WHERE  d.das_station = s.id AND svcid = "trrq" ORDER  BY d.date_attached DESC;
+---------------+-------------+------+-----------+---------------------+--------------+---------------------+---------------------+
| ingester      | das_station | size | namespace | date_attached       | date_started | date_finished       | date_detached       |
+---------------+-------------+------+-----------+---------------------+--------------+---------------------+---------------------+
| ca-adsdas2-p1 |          11 | NULL | NULL      | Jan-20-2016 1:42 PM | NULL         | NULL                | Jan-21-2016 3:16 PM |
| ca-adsdas2-p1 |          11 | NULL | NULL      | Dec-21-2015 7:25 PM | NULL         | Dec-26-2015 9:22 PM | Jan-20-2016 1:33 PM |
+---------------+-------------+------+-----------+---------------------+--------------+---------------------+---------------------+

如果das_station = 11，它应该在命名空间中说“BPN1”，而不是空。

Answer 1

通过在WHEN中包含namespace_port来解决这个问题：

SELECT s.name AS 'ingester',
    d.dev_used AS 'size',
    Cast(CASE WHEN (d.namespace_port = 4015 AND d.das_station IN (11,22,23)) THEN 'BPN1' WHEN (d.namespace_port = 4015 AND d.das_station NOT IN (11,22,23)) THEN 'SJC12' WHEN d.namespace_port = 4016 THEN 'SJC17' WHEN d.namespace_port = 4017 THEN 'SJC18' WHEN d.namespace_port = 4018 THEN 'SJC19' WHEN d.namespace_port = 4019 THEN 'SJC5' WHEN d.namespace_port = 4020 THEN 'SJC6'  WHEN d.namespace_port = 4021 THEN 'SJC7' WHEN d.namespace_port = 4022 THEN 'SJC8'  WHEN d.namespace_port = 4023 THEN 'SJC9' WHEN d.namespace_port = 4024 THEN 'SJC10' WHEN d.namespace_port = 4025 THEN 'SJC11' WHEN d.namespace_port = 4026 THEN 'SJC20' WHEN d.namespace_port = 4027 THEN 'SJC13' WHEN d.namespace_port = 4028 THEN 'SJC14' WHEN d.namespace_port = 4029 THEN 'SJC15' WHEN d.namespace_port = 4030 THEN 'SJC16' END AS CHAR) AS namespace,
    Date_format(d.date_attached, '%b-%e-%Y %l:%i %p') AS 'date_attached',
    Date_format(d.replication_started, '%b-%e-%Y %l:%i %p') AS 'date_started',
    Date_format(d.replication_completed, '%b-%e-%Y %l:%i %p') AS 'date_finished',
    Date_format(d.date_detached, '%b-%e-%Y %l:%i %p') AS 'date_detached'
FROM   das.stations s,
       das.device d
WHERE  d.das_station = s.id
AND svcid = "96wa"
ORDER  BY d.date_attached DESC

导致以下结果：

+------------------+--------------+-----------+---------------------+---------------------+----------------------+---------------------+
| ingester         | size         | namespace | date_attached       | date_started        | date_finished        | date_detached       |
+------------------+--------------+-----------+---------------------+---------------------+----------------------+---------------------+
| bpn-dasingest-p2 |         NULL | NULL      | Mar-29-2017 7:41 AM | NULL                | NULL                 | Mar-30-2017 8:58 AM |
| bpn-dasingest-p2 | 247547875328 | BPN1      | Mar-27-2017 7:55 AM | Mar-27-2017 9:33 AM | Mar-27-2017 12:27 PM | Mar-29-2017 7:41 AM |
+------------------+--------------+-----------+---------------------+---------------------+----------------------+---------------------+

MySQL案例语句中的额外列条件不起作用

1 个答案: