added Join to select queries

.gitignore

@@ -1,4 +1,5 @@
 vendor
 composer.lock
 .php_cs.cache
+.phpunit.result.cache
 coverage

src/Query/Traits/HasJoin.php

@@ -0,0 +1,65 @@
+<?php
+declare(strict_types = 1);
+
+namespace SimpleCrud\Query\Traits;
+
+use InvalidArgumentException;
+use RuntimeException;
+use SimpleCrud\Row;
+use SimpleCrud\RowCollection;
+use SimpleCrud\Table;
+
+trait HasJoin
+{
+    public function join(Table $table2, string $condition = null, ...$values)
+    {
+        $table1 = $this->table;
+
+        //Has One
+        if ($field = $table1->getJoinField($table2)) {
+            $this->query
+                ->join(
+                    'LEFT',
+                    (string) $table2,
+                    sprintf('%s = %s', $field, $table2->id)
+                );
+
+        //Has many
+        } elseif ($field = $table->getJoinField($table1)) {
+            $this->query
+                ->join(
+                    'LEFT',
+                    (string) $table2,
+                    sprintf('%s = %s', $field, $table1->id)
+                );
+
+        //Has many to many
+        } elseif ($joinTable = $table1->getJoinTable($table2)) {
+            $field1 = $joinTable->getJoinField($table1);
+            $field2 = $joinTable->getJoinField($table2);
+
+            $this->query
+                ->join(
+                    'LEFT',
+                    (string) $joinTable,
+                    sprintf('%s = %s', $field1, $table1->id)
+                )
+                ->join(
+                    'LEFT',
+                    (string) $table2,
+                    sprintf('%s = %s', $field2, $table2->id)
+                );
+
+        } else {
+            throw new RuntimeException(
+                sprintf('The tables %s and %s are not related', $table1, $table2)
+            );
+        }
+
+        if ($condition) {
+            $this->query->catJoin($condition, $values);
+        }
+
+        return $this;
+    }
+}

src/Query/Traits/HasWhere.php

@@ -11,6 +11,8 @@
 
 trait HasWhere
 {
+    use HasJoin;
+
     public function where(string $condition, ...$values)
     {
         $this->query->where($condition, ...$values);