Converting one to many to one to one table in SQL

Question

I need some SQL guidance. I have a table (A) that looks like this (note the rows should be unique by ID+CommType):

Member ID	CommType	Consent	Emailable
1	News	Yes	Yes
2	News	Yes	No
1	Surveys	No
2	Surveys	Yes	Yes
1	Events	Yes
3	News	No	No

Which I want to end up as follows (unique row by Member ID).

For added complexity, the rules for the final table values for each CommType:

(Yes if both Consent and Emailable = Yes for CommType)
(No if Emailable = No for CommType)
(NULL if Emailable = null or no row for CommType)

Member ID	News	Surveys	Events
1	Yes
2	No	Yes
3	No

Answer 1

Don't know why you got downvoted - it's a good question and you clearly took the time to write it out with as much context as possible.

You can try the following - note this assumes you have a reasonable number of different CommTypes and you know all the possible values:

SELECT member_id
, MIN(CASE WHEN CommType='News' THEN CASE WHEN Consent = 'Yes' AND Emailable='Yes' THEN 'Yes' WHEN Emailable = 'No' THEN 'No' END END) AS news
, MIN(CASE WHEN CommType='Surveys' THEN CASE WHEN Consent = 'Yes' AND Emailable='Yes' THEN 'Yes' WHEN Emailable = 'No' THEN 'No' END END) AS surveys
, MIN(CASE WHEN CommType='Events' THEN CASE WHEN Consent = 'Yes' AND Emailable='Yes' THEN 'Yes' WHEN Emailable = 'No' THEN 'No' END END) AS events
-- , ..., do the same for each possible CommType
FROM your_table
GROUP BY member_id