bool_in bool_out float8_in float8_out hash_bytes_uint32 hash_bytes_uint32_extended int4_in int4_out int8_in int8_out pg_datan pg_datan2 pg_dcos pg_dsin pg_hashfloat8 pg_hashfloat8extended pg_hashint8 pg_hashint8extended pg_hashtext pg_hashtextextended pg_interval_cmp pg_interval_justify_hours pg_interval_pl pg_timestamp_mi pg_timestamp_mi_interval pg_timestamp_pl_interval pg_timestamptz_in pg_timestamptz_out

pg_datan() float8 pg_datan ( float8  arg1 ) Return the arctan of arg1 (radians) Note PostgreSQL function: Datum datan(PG_FUNCTION_ARGS)