How SQL SELECT queries 2 values at a time

For example, in the database, a key hide=y and hide=n to achieve the same amount of data equal to Y and n how to write
The SQL statement is not very understanding I wrote this, although no error
SELECT * FROM blog WHERE type= ' $type ' $author and hide= ' y ' and hide= ' n ' $condition $limit
But it doesn't even show.
SELECT * FROM blog WHERE type= ' $type ' $author and hide= ' y ' $condition $limit
This can be done, but this can show that equals y does not achieve equal to N.

Reply to discussion (solution)

What are your $author $condition, respectively?

Similar, modify to see

SELECT * from ' blog '  WHERE ' type ' = ' $type '     and ' author ' = ' $author '     and ' hide ' in ("Y", "n") LIMIT

You can use it or not. Why use and AH ~ How can be equal to Y and equal to n

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