Postgres 19 beta 4

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select version();


version


PostgreSQL 19beta4 (Debian 19~beta4-1.pgdg13+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 14.2.0-19) 14.2.0, 64-bit



SELECT 1


-- new in 19: ignore nulls in window functions
select t, v, last_value(v) ignore nulls over (order by t) as carried
from (values (1,10), (2,null), (3,null), (4,40), (5,null)) r(t, v);


t
v
carried


1
10
10

2
null
10

3
null
10

4
40
40

5
null
40



SELECT 5


// C demo
#include "postgres.h"
#include "fmgr.h"
#include "varatt.h"
#include <stdlib.h>

PG_MODULE_MAGIC;

PG_FUNCTION_INFO_V1(random_bytea);

Datum
random_bytea(PG_FUNCTION_ARGS)
{
    int32     numbytes;
    bytea *   randbytea;
    char *    cur_data_ptr;
    long int  lastrand;
    long int  remaining;

    numbytes = PG_GETARG_INT32(0);
    randbytea = palloc(VARHDRSZ + numbytes);
    SET_VARSIZE(randbytea, VARHDRSZ + numbytes);
    cur_data_ptr = VARDATA(randbytea);
    remaining = 0;
    while ( (numbytes--) > 0) {
         remaining = remaining >> 8;
         lastrand = lastrand >> 8;
         if (remaining < 256) {
            lastrand = random();
            remaining = RAND_MAX;
         }
         *(cur_data_ptr++) = (unsigned char) lastrand;
    }

    PG_RETURN_BYTEA_P(randbytea);
}

built fiddle.1.so


create or replace function random_bytea(integer) returns bytea
	as 'fiddle.1','random_bytea'
	language c strict;

CREATE FUNCTION


select
  length(randombytes),
  encode(substring(randombytes for 8),'hex')
from (select random_bytea(1024*1024*16) as randombytes) z;


length
encode


16777216
5c1b98bb32b754bb



SELECT 1


create table customer (id int primary key, name text not null);
create table product (id int primary key, name text not null, price numeric(6,2) not null);
create table orders (id int primary key, customer_id int not null references customer, ordered_on date not null);
create table order_line (order_id int references orders, product_id int references product, qty int not null, primary key (order_id, product_id));
insert into customer values (1,'ann'), (2,'bob'), (3,'cat');
insert into product values (1,'widget',2.50), (2,'gadget',7.00), (3,'gizmo',12.00);
insert into orders select n, 1+n%3, date '2026-01-01' + n*7 from generate_series(0,51) n;
insert into order_line select o.id, p.id, 1+(o.id*p.id)%5 from orders o cross join product p where (o.id+p.id)%2=0 or p.id=1;

CREATE TABLE



CREATE TABLE



CREATE TABLE



CREATE TABLE



INSERT 0 3



INSERT 0 3



INSERT 0 52



INSERT 0 104


-- echarts demo
with
  mon as (select generate_series(date '2026-01-01', date '2026-12-01', interval '1 month')::date m)
, rev as
    ( select p.name, mon.m, coalesce(sum(l.qty*p.price),0) r
      from
        product p cross join
        mon left join
        (orders o join order_line l on l.order_id = o.id) on date_trunc('month', o.ordered_on) = mon.m and l.product_id = p.id
      group by p.name, mon.m )
select
  json_build_object
  ( 'tooltip', json_build_object('trigger','axis')
  , 'legend', json_build_object()
  , 'xAxis', json_build_object('type','category','data',(select json_agg(to_char(m,'Mon') order by m) from mon))
  , 'yAxis', json_build_object('type','value')
  , 'series', (select json_agg(json_build_object('name',name,'type','bar','stack','revenue','data',data) order by name) from (select name, json_agg(r order by m) data from rev group by name) s)
  ) as option;


option


{"tooltip" : {"trigger" : "axis"}, "legend" : {}, "xAxis" : {"type" : "category", "data" : ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]}, "yAxis" : {"type" : "value"}, "series" : [{"name" : "gadget", "type" : "bar", "stack" : "revenue", "data" : [70.00, 35.00, 42.00, 49.00, 21.00, 63.00, 42.00, 63.00, 35.00, 42.00, 49.00, 21.00]}, {"name" : "gizmo", "type" : "bar", "stack" : "revenue", "data" : [108.00, 36.00, 84.00, 96.00, 84.00, 72.00, 60.00, 108.00, 36.00, 144.00, 36.00, 84.00]}, {"name" : "widget", "type" : "bar", "stack" : "revenue", "data" : [37.50, 25.00, 27.50, 37.50, 30.00, 32.50, 37.50, 35.00, 25.00, 37.50, 27.50, 30.00]}]}



SELECT 1


-- mermaid demo
select
  concat_ws
  ( e'\n'
  , 'erDiagram'
  , ( select
        string_agg
        ( format
          ( e'  %s {\n%s\n  }'
          , c.relname
          , ( select string_agg(concat_ws(' ', '   ', format_type(a.atttypid, null), a.attname, nullif(concat_ws(', ', case when a.attnum = any(pk.conkey) then 'PK' end, case when exists(select from pg_constraint f where f.conrelid = c.oid and f.contype = 'f' and a.attnum = any(f.conkey)) then 'FK' end), '')), e'\n' order by a.attnum)
              from pg_attribute a
              where a.attrelid = c.oid and a.attnum > 0 and not a.attisdropped )
          )
        , e'\n' order by c.relname
        )
      from pg_class c left join pg_constraint pk on pk.conrelid = c.oid and pk.contype = 'p'
      where c.relnamespace = 'public'::regnamespace and c.relkind = 'r' )
  , ( select string_agg(format('  %s }o--|| %s : "%s"', conrelid::regclass, confrelid::regclass, (select string_agg(attname, ', ') from pg_attribute where attrelid = conrelid and attnum = any(conkey))), e'\n' order by conrelid::regclass::text, confrelid::regclass::text)
      from pg_constraint
      where contype = 'f' and connamespace = 'public'::regnamespace )
  ) as diagram;


diagram


erDiagram
  customer {
    integer id PK
    text name
  }
  order_line {
    integer order_id PK, FK
    integer product_id PK, FK
    integer qty
  }
  orders {
    integer id PK
    integer customer_id FK
    date ordered_on
  }
  product {
    integer id PK
    text name
    numeric price
  }
  order_line }o--|| orders : "order_id"
  order_line }o--|| product : "product_id"
  orders }o--|| customer : "customer_id"



SELECT 1
t	v	carried
1	10	10
2	null	10
3	null	10
4	40	40
5	null	40