我正在尝试重命名我具有READ-ONLY访问权限的数据库的一列的值。我还想将两个值组合成一个。我正在使用SQL CASE查询，但它正在错误地转换值。这是我的SQL：
SELECT
DATE(appraisal.created_time),
appraisal_steps.title,
Count(appraisal.appraisal_id),
case appraisal_steps.title
when "archive" then "A_Archived"
when "on_sale" then "J_Selling"
when "under_evaluation" then "F_Evaluating"
when "evaluated" then "H_Appraisal Complete"
when "pending" then "B_Pending"
when "crap" then "C_Not For Lofty"
when "waiting_internal_expert_evaluation" then "D_Unclaimed"
when ("expert_needs_information" OR "admin_needs_information") then "E_Waiting"
when "seller_answered_to_expert_question" then "G_Needs_Attn"
when "ready_to_be_sold" then "I_Ready"
else "wtf"
end as Status
FROM
appraisal
INNER JOIN appraisal_steps ON appraisal.`status` = appraisal_steps.step_id
WHERE
appraisal.powersale = 0
GROUP BY
DATE(appraisal.created_time),
appraisal_steps.title
ORDER BY
appraisal_steps.title DESC, status
结果对于某些状态是正确的（是复数stati？:)但是seller_answered_to_expert_question被转换为“E_Waiting”，这是不正确的。
如果我更改“When”子句的顺序，则不同的stati工作并且不起作用。
我做错了什么？
答案 0 :(得分：2)
问题是格式为CASE的{{1}}语句不允许通过CASE field WHEN criteria THEN END或OR的多个条件，因此AND中的第二个条件} line没有与title字段中的值进行比较，在这种情况下，“G_Needs_Attn”，“I_Ready”或“wtf”中没有任何内容被删除。
您可以通过以下几种方式解决此问题：
将您的WHEN行分成两行：
OR或者使用 when "expert_needs_information" then "E_Waiting"
when "admin_needs_information" then "E_Waiting"
语句的格式：
CASE此格式允许评估多个字段的条件，或同一字段的多个条件。您也可以使用 SELECT
DATE(appraisal.created_time),
appraisal_steps.title,
Count(appraisal.appraisal_id),
case when appraisal_steps.title = "archive" then "A_Archived"
when appraisal_steps.title = "on_sale" then "J_Selling"
when appraisal_steps.title = "under_evaluation" then "F_Evaluating"
when appraisal_steps.title = "evaluated" then "H_Appraisal Complete"
when appraisal_steps.title = "pending" then "B_Pending"
when appraisal_steps.title = "crap" then "C_Not For Lofty"
when appraisal_steps.title = "waiting_internal_expert_evaluation" then "D_Unclaimed"
when appraisal_steps.title = "expert_needs_information" OR appraisal_steps.title = "admin_needs_information" then "E_Waiting"
when appraisal_steps.title = "seller_answered_to_expert_question" then "G_Needs_Attn"
when appraisal_steps.title = "ready_to_be_sold" then "I_Ready"
else "wtf"
end as Status
FROM
appraisal
INNER JOIN appraisal_steps ON appraisal.`status` = appraisal_steps.step_id
WHERE
appraisal.powersale = 0
GROUP BY
DATE(appraisal.created_time),
appraisal_steps.title
ORDER BY
appraisal_steps.title DESC, status
作为该行。
以下是一个演示，展示了错误的when appraisal_steps.title IN ("expert_needs_information","admin_needs_information") then "E_Waiting"最终如何成为一个包罗万象：SQL Fiddle