Where 'foo' OR 'bar' AND 'lol' OR 'rofl' MySQL

In what order would this be evaluated. My intension is that if it finds either foo or bar, i开发者_运维问答t would also search for lol and rofl.

Is this totally in the woods? And if so, how would one evaluate an expression like that.

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The AND operator has higher precedence than OR in MySql, so your current expression evaluates as:

WHERE 'foo' OR ('bar' AND 'lol') OR 'rofl'

Add parentheses to the expression if you want to force the evaluation order:

WHERE ('foo' OR 'bar') AND ('lol' OR 'rofl')

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AND will be processed first, after that OR will be processed. So, it will be:

'foo' OR ('bar' AND 'lol') OR 'rofl'

After that, it is left to right order.

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take a look at the documentation - AND has a higher precedence, so it would be like this:

WHERE 'foo' OR ( 'bar' AND 'lol' ) OR 'rofl'

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SELECT
  Id, Name
FROM
  TestTable
WHERE
    (Name = 'foo') OR (Name = 'bar') AND (Name = 'lol') OR (Name = 'rofl')

Will give you the following result in MS SQL Server:

1 foo
4 rofl

So it seems it will combine bar AND lol and evals foo and rofl seperately like this:

SELECT
      Id, Name
    FROM
      TestTable
    WHERE
        (Name = 'foo') OR ((Name = 'bar') AND (Name = 'lol')) OR (Name = 'rofl')

What you probably want to do is (technically):

SELECT
      Id, Name
    FROM
      TestTable
    WHERE
        ((Name = 'foo') OR (Name = 'bar')) AND ((Name = 'lol') OR (Name = 'rofl'))