How exactly does using OR in a MySQL statement differ with/without parentheses?

by

This is because OR has lower operator precedence than AND. Whenever the DB sees an expression like

A AND B OR C

the AND is evaluated first, i.e. it is equivalent to

(A AND B) OR C

So if you explicitly want

A AND (B OR C)

instead, you must put in the parentheses.

This is btw not specific to SQL. The order of precedence of these operators is the same in all programming languages I know (i.e. at least C, C++, C#, Java and Unix shell scripts).

More Related Contents:

  1. MySQL Insert query doesn’t work with WHERE clause
  2. Delete from two tables in one query
  3. Why would an IN condition be slower than “=” in sql?
  4. PostgreSQL GROUP BY different from MySQL?
  5. GROUP BY behavior when no aggregate functions are present in the SELECT clause
  6. Fulltext Search with InnoDB
  7. MySQL’s now() +1 day
  8. Delete sql rows where IDs do not have a match from another table
  9. Rewriting mysql select to reduce time and writing tmp to disk
  10. How do I convert from BLOB to TEXT in MySQL?
  11. Can you access the auto increment value in MySQL within one statement?
  12. Which SQL query is better, MATCH AGAINST or LIKE?
  13. What does DELIMITER // do in a Trigger?
  14. MySQL, Get users rank
  15. Mysql: how to select groups having certain values?
  16. How to fill date gaps in MySQL?
  17. Boolean vs tinyint(1) for boolean values in MySQL
  18. MySQL full text search for words with three or less letters
  19. MySQL: “The SELECT would examine more than MAX_JOIN_SIZE rows”
  20. Function for week of the month in mysql
  21. MySQL’s alternative to T-SQL’s WITH TIES
  22. Find rows that have the same value on a column in MySQL
  23. what is the difference between GROUP BY and ORDER BY in sql
  24. Two single-column indexes vs one two-column index in MySQL?
  25. VARCHAR as foreign key/primary key in database good or bad?
  26. MySQL SELECT x FROM a WHERE NOT IN ( SELECT x FROM b ) – Unexpected result
  27. MySql bulk load command line tool
  28. ALTER TABLE without locking the table?
  29. MySQL: Typecasting NULL to 0
  30. How to get the byte size of resultset in an SQL query?

Leave a Comment