sql - OR WHERE and AND in mySQL Query

Question

Basically, I'm trying to get data from an SQL based on two different groups, t.type has to equal single and t.status has to equal 1 but as for t.org I want to it get both DUAL and RA, here's what I attempted to no avail.

SELECT 
    COUNT( p.tID ) 
FROM 
    ticket AS t 
INNER JOIN 
    people AS p ON t.ID = p.tID 
WHERE 
    t.type = 'single' AND t.status='1' AND t.org = 'RA' OR t.org = 'DUAL'

I'm pretty sure theirs a way to get this query working, just not in my head

Answer 1

AND has higher precedence than OR, so your existing expression is currently evaluated as:

WHERE 
    (t.type = 'single' AND t.status='1' AND t.org = 'RA') OR t.org = 'DUAL'

To force alternative logic, one needs to include explicit parentheses:

WHERE 
    t.type = 'single' AND t.status='1' AND (t.org = 'RA' OR t.org = 'DUAL')

However, in this case, one can use MySQL's IN() operator instead of OR:

WHERE 
    t.type = 'single' AND t.status='1' AND t.org IN ('RA','DUAL')