没有函数匹配给定的名称和参数类型。 您可能需要添加显式类型转换 - Postgresql（IF 函数）

Question

I tried to run the below query:

SELECT account_no, month_id, IF (product_category = 'Services', 'ServicesMarketing', product_category) AS product_category, revenue  
FROM public.revenue_raw_data

Error I got:

 ERROR: function if(boolean, unknown, character) does not exist LINE 1: SELECT account_no, month_id, IF (product_category = 'Service... ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. SQL state: 42883 Character: 30

My Data:

Answer 1

There is no IF() function in SQL (or in Postgres).

In Postgres (and standard SQL) you would use a CASE expression

SELECT account_no, month_id, 
       case 
         when product_category = 'Services'
              then 'ServicesMarketing'
         else product_category
       end AS product_category, 
       revenue 
FROM public.revenue_raw_data

(Note that I am just guessing what you think that if() should do)