add_date_int add_interval_interval add_timestamptz_interval bool_in bool_out cstring2text date_in date_out date_to_timestamp date_to_timestamptz float_exp float_ln float_log10 float_round interval_cmp interval_in interval_make interval_out minus_date_date minus_date_int minus_timestamptz_interval minus_timestamptz_timestamptz mul_interval_double text2cstring text_cmp text_copy text_initcap text_lower text_out text_upper textcat_text_text time_in time_out timestamp_in timestamp_out timestamp_to_date timestamptz_in timestamptz_out timestamptz_shift timestamptz_to_date

interval_out() char * interval_out ( const Interval *  interv ) Return the string representation of an interval. Parameters [in] interv Interval Note PostgreSQL function: interval_out(PG_FUNCTION_ARGS) Please refer to the PostgreSQL documentation https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-INTERVAL-OUTPUT for a detailed account of the output format, which depends on the interval style specified at the initialization of the MEOS library (postgres by default)