Added FULL JOIN support to QueryBuilder (#7310)

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|      Q       |   A
|------------- | -----------
| Type         | feature
| Fixed issues | #7301 

#### Summary

Added [FULL
JOIN](https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-JOIN)
support to QueryBuilder.

Author: Bilge

src/Query/Join.php

@@ -29,4 +29,9 @@ public static function right(string $table, string $alias, ?string $condition):
     {
         return new self('RIGHT', $table, $alias, $condition);
     }
+
+    public static function full(string $table, string $alias, ?string $condition): Join
+    {
+        return new self('FULL', $table, $alias, $condition);
+    }
 }

src/Query/QueryBuilder.php

@@ -891,6 +891,32 @@ public function rightJoin(string $fromAlias, string $join, string $alias, ?strin
         return $this;
     }
 
+    /**
+     * Creates and adds a full join to the query.
+     *
+     * <code>
+     *     $qb = $conn->createQueryBuilder()
+     *         ->select('u.name')
+     *         ->from('users', 'u')
+     *         ->fullJoin('u', 'phonenumbers', 'p', 'p.is_primary = 1');
+     * </code>
+     *
+     * @param string      $fromAlias The alias that points to a from clause.
+     * @param string      $join      The table name to join.
+     * @param string      $alias     The alias of the join table.
+     * @param string|null $condition The condition for the join.
+     *
+     * @return $this This QueryBuilder instance.
+     */
+    public function fullJoin(string $fromAlias, string $join, string $alias, ?string $condition = null): self
+    {
+        $this->join[$fromAlias][] = Join::full($join, $alias, $condition);
+
+        $this->sql = null;
+
+        return $this;
+    }
+
     /**
      * Sets a new value for a column in a bulk update query.
      *

tests/Query/QueryBuilderTest.php

@@ -157,6 +157,18 @@ public function testSelectWithRightJoin(): void
         self::assertEquals('SELECT u.*, p.* FROM users u RIGHT JOIN phones p ON p.user_id = u.id', (string) $qb);
     }
 
+    public function testSelectWithFullJoin(): void
+    {
+        $qb   = new QueryBuilder($this->conn);
+        $expr = $qb->expr();
+
+        $qb->select('u.*', 'p.*')
+            ->from('users', 'u')
+            ->fullJoin('u', 'phones', 'p', $expr->eq('p.user_id', 'u.id'));
+
+        self::assertEquals('SELECT u.*, p.* FROM users u FULL JOIN phones p ON p.user_id = u.id', (string) $qb);
+    }
+
     public function testSelectWithAndWhereConditions(): void
     {
         $qb = new QueryBuilder($this->conn);