feature #23: create route for citizen

src/main/resources/sql/functions/citizen/find_citizens.sql

@@ -0,0 +1,43 @@
+create or replace function find_citizens(
+    search text default null,
+    direction text default 'desc',
+    sort text default 'created_at',
+    "limit" int default 50,
+    "offset" int default 0,
+    out resource json,
+    out total int
+) language plpgsql as
+$$
+begin
+    select json_agg(t), (select count(id) from citizen)
+    into resource, total
+    from (
+        select
+            z.*
+        from citizen as z
+        where "search" is null or (
+            (name->'first_name')::text ilike '%'||"search"||'%' or
+            (name->'last_name')::text ilike '%'||"search"||'%'
+        )
+        order by
+        case direction when 'asc' then
+            case sort
+                when 'name' then (z.name->'first_name')::text
+                when 'created_at' then z.created_at::text
+                else null
+            end
+        end,
+        case direction when 'desc' then
+            case sort
+                when 'name' then (z.name->'first_name')::text
+                when 'created_at' then z.created_at::text
+            end
+        end
+        desc,
+        z.created_at desc
+        limit "limit" offset "offset"
+    ) as t;
+end;
+$$;
+
+-- drop function if exists find_citizens(text, text, text, int, int);