sql - 错误 : operator does not exist: character varying = boolean

Question

我有以下查询:

SELECT
CASE
    tbl_appointment_types."name" 
    WHEN tbl_appointment_types."name" LIKE 'Refill-ART' THEN
    'Re-Fill' 
    WHEN tbl_appointment_types."name" = 'Enhanced Adherence'::character varying THEN
    'Enhanced Adherence' 
    WHEN tbl_appointment_types."name" = 'PHARMACY APPOINTMENT'::character varying THEN
    'Re-Fill' ELSE tbl_appointment_types."name" 
END 
FROM
    tbl_appointment INNER JOIN tbl_appointment_types ON tbl_appointment_types."id" = tbl_appointment.app_type_1 
GROUP BY
    tbl_appointment_types."name";

当我尝试运行它时，出现以下错误:

> ERROR:  operator does not exist: character varying = boolean
  LINE 4:  WHEN tbl_appointment_types."name" LIKE 'Refill-ART' THEN
           ^
  HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.

> Time: 0.054s

如何解决以下问题？

Answer 1

CASE 表达式有两种形式:

一种“简短”形式，仅支持相等性，您首先声明表达式，然后声明应与之比较的值(使用 =)，例如

 CASE some_column
    WHEN 1 THEN 'One'
    WHEN 2 THEN 'Two'
    ELSE 'Something else'
 END

或者更详细的版本，您可以为每个 WHEN 使用不同的条件。但在那种情况下，您可以不在 CASE 之后使用表达式:

 CASE -- nothing here!
    WHEN some_column = 1 THEN 'One'
    WHEN some_column = 2 THEN 'Two'
    ELSE 'Something else'
 END

因此您需要将 CASE 表达式写为:

CASE -- nothing here!
   WHEN tbl_appointment_types."name" LIKE 'Refill-ART' THEN 'Re-Fill' 
   WHEN tbl_appointment_types."name" = 'Enhanced Adherence' THEN 'Enhanced Adherence' 
   WHEN tbl_appointment_types."name" = 'PHARMACY APPOINTMENT' THEN 'Re-Fill' 
   ELSE tbl_appointment_types."name" 
END 

---

使用不带通配符的 LIKE 没有任何意义。 "name"LIKE 'Refill-ART' 与 "name"= 'Refill-ART' 相同。

您的意思可能是 "name"LIKE 'Refill-ART%'(注意末尾的 %)