Why you should use parentheses with AND & OR in SQL

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Senior Data Engineer • Contractor / Freelancer • GCP & AWS Certified
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If you filter the data in SQL with WHERE using multiple logical conditions tied with AND & OR, PLEASE use the parentheses them accordingly.
Because if you don't, your fellow team members are going to have a harder time understanding your intent.
You might also get unintended results based on how they are resolved:
... operators with the same precedence are left associative. This means that those operators are grouped together starting from the left and moving right.
AND has a higher order of precedence than OR, therefore, in the example below:
is_paid AND is_shipped OR customer_is_on_contract AND is_first_time_buyer
is equivalent to
( is_paid AND is_shipped) OR (customer_is_on_contract AND is_first_time_buyer).
It should also be noted that for comparison operators parentheses are required in order to resolve ambiguity since they are not associative like NOT/AND/OR.
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