获取时间中的微秒

CREATE OR REPLACE FUNCTION public.milliseconds(
	texpression timestamp without time zone DEFAULT clock_timestamp(
	))
    RETURNS integer
    LANGUAGE 'plpgsql'

    COST 100
    IMMUTABLE 
AS $BODY$
	DECLARE
		mill float8;
BEGIN
		return TO_CHAR (tExpression, 'US')::int;
		/*
		mill := date_part('seconds' ,tExpression);
        RETURN (mill - (mill::int))*1000;
		*/

END;
$BODY$;

ALTER FUNCTION public.milliseconds(timestamp without time zone)
    OWNER TO postgres;

COMMENT ON FUNCTION public.milliseconds(timestamp without time zone)
    IS '获取时间中的微秒';