Select Statement With Multiple Parameter Values

I want to create a query where the parameter values are essentially OR options, but want to use values from a php array. It sounds confusing, but let me show you and you will understand. I want to do something like this:

SELECT * from TABLENAME WHERE columnname =1 OR columname = 3 OR columname = 8 etc.

it seems like I should just be able to do something like
WHERE columnname = 1,3,8

but that obviously doesn't work.

Lets say that I have a php array with values of (1,3,8), how can I select the records from a column that have any of those values? I need a shorthand method because the values will be dynamic. What am I missing?

 

Sorry, the above was a brain cramp post. Forgot about IN.