The ICONV function converts data in external form such as dates to their internal form.
expression1 evaluates to the data that the conversion is to be performed upon. expression2 should evaluate to the conversion code that is to be performed against the data.
If the conversion code used assumes a numeric value and a non-numeric value is passed then the original value in expression1 is returned unless the emulation option iconv_nonnumeric_return_null is set.
Also see OCONV.
In this example ICONV returns the internal form of the date May 27, 1997.