MySQL: Question about SELECT WHERE AND/OR

Question

I'm trying to write a query that returns the same result from three different events, but I think I am doing it wrong. I can run my query against one event ID and it works. How can I select all three? Here's what I have so far:

SELECT * FROM `Registrations` 
WHERE `Role` = "Attendee" AND `RegistrationStatus_ID` = "1" AND `DigSignature` IS NULL
    AND `Event_ID` = "147" OR `Event_ID` = "155" OR `Event_ID` = "160"

Answer 1

SELECT * 
FROM `Registrations`  
WHERE `Role` = "Attendee" 
    AND `RegistrationStatus_ID` = "1" 
    AND `DigSignature` IS NULL 
    AND `Event_ID` in ("147", "155", "160")

Answer 2

You need to wrap OR statements in parentheses:

SELECT * FROM `Registrations` 
WHERE `Role` = "Attendee" AND `RegistrationStatus_ID` = "1" AND `DigSignature` IS NULL
    AND (`Event_ID` = "147" OR `Event_ID` = "155" OR `Event_ID` = "160")

Answer 3

SELECT * FROM `Registrations` 
WHERE `Role` = "Attendee" AND `RegistrationStatus_ID` = "1" AND `DigSignature` IS NULL
    AND (`Event_ID` = "147" OR `Event_ID` = "155" OR `Event_ID` = "160")

When you're mixing AND and OR, it's helpful to use parens to group things together. Even when it's not necessary for logic, it's sometimes helpful for others to understand your intentions.

Answer 4

AND and OR have equal precedence.

SELECT * FROM `Registrations` 
WHERE `Role` = "Attendee" AND `RegistrationStatus_ID` = "1" AND `DigSignature` IS NULL
    AND (`Event_ID` = "147" OR `Event_ID` = "155" OR `Event_ID` = "160")