getting datatype of array elements

hi,

with the following statement, i get the datatype of a column with help of
its name and the tableoid:

SELECT typname FROM pg_attribute LEFT JOIN pg_type ON atttypid=typelem
WHERE attrelid=18210 AND attname='email';

but if the columns datatyp is an array, that doesn't work.
i'd like to get the basic datatype (the datatype of the array elements) then.

any ideas?

thanks,
 moritz

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