Correct inner join to use proper aliases (#1978)

"_" was used for all the internal json_agg aliases. Now an alias
with "_" plus a local table name is used.

Co-authored-by: Cole Arendt <cole.arendt@outlook.com>

test/fixtures/schema.sql

@@ -2347,4 +2347,22 @@ create table suppliers_trade_unions(
   supplier_id int references suppliers(id),
   trade_union_id int references trade_unions(id),
   primary key (supplier_id, trade_union_id)
-);
+);
+
+
+CREATE TABLE client (
+  id int primary key
+, name text
+);
+
+CREATE TABLE contact (
+  id int primary key
+, name text
+, clientid int references client(id)
+);
+
+CREATE TABLE clientinfo (
+  id serial primary key
+, clientid int unique references client(id)
+, other text
+);