1

我正在使用 CASE 清理表格中的一些州缩写，但它的工作方式与逻辑相反。我单独选择了长度以表明长度计算正确，所以我认为这是关闭的 CASE 逻辑

当我查询...

SELECT billing_state,
       length(billing_state),
       CASE billing_state
         WHEN length(billing_state) > 2 THEN (select state_abbr from lkup_states where upper(state_name) = billing_state)
         WHEN length(billing_state) = 2 THEN upper(billing_state)
         ELSE 'UNKNOWN'
       END as billing_state_fixed           
  FROM accounts
+---------------+-----------------------+---------------------+
| billing_state | length(billing_state) | billing_state_fixed |
+---------------+-----------------------+---------------------+
| GA            |                     2 | NULL                |
| Alabama       |                     7 | ALABAMA             |
| MS            |                     2 | NULL                |
| FL            |                     2 | NULL                |
| NULL          |                  NULL | UNKNOWN             |
+---------------+-----------------------+---------------------+

然而，当我进入这个奇怪的逻辑时，它就起作用了。 

SELECT billing_state,
       length(billing_state),
       CASE billing_state
         WHEN length(billing_state) = 2 THEN (select state_abbr from lkup_states where upper(state_name) = billing_state)
         WHEN length(billing_state) <> 2 THEN upper(billing_state)
         ELSE 'UNKNOWN'
       END as billing_state_fixed           
  FROM accounts

+---------------+-----------------------+---------------------+
| billing_state | length(billing_state) | billing_state_fixed |
+---------------+-----------------------+---------------------+
| GA            |                     2 | GA                  |
| Alabama       |                     7 | AL                  |
| MS            |                     2 | MS                  |
| FL            |                     2 | FL                  |
| NULL          |                  NULL | UNKNOWN             |
+---------------+-----------------------+---------------------+

有人可以试试这个吗？

4

1 回答 1

1

根据docs，您的语法不太正确。

你糊涂了CASE value WHEN compare_value和CASE WHEN expression。

你可能想要的是：

SELECT billing_state,
       length(billing_state),
       CASE
         WHEN length(billing_state) > 2 THEN (select state_abbr from lkup_states where upper(state_name) = billing_state)
         WHEN length(billing_state) = 2 THEN upper(billing_state)
         ELSE 'UNKNOWN'
       END as billing_state_fixed           
  FROM accounts
于 2012-10-15T20:04:04.163 回答