diff --git a/src/Query/Mysql/JsonContains.php b/src/Query/Mysql/JsonContains.php
index 23e2e0e1..c72e968d 100644
--- a/src/Query/Mysql/JsonContains.php
+++ b/src/Query/Mysql/JsonContains.php
@@ -3,6 +3,7 @@
 namespace DoctrineExtensions\Query\Mysql;
 
 use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
 use Doctrine\ORM\Query\Parser;
 use Doctrine\ORM\Query\SqlWalker;
 use Doctrine\ORM\Query\TokenType;
@@ -10,15 +11,23 @@
 use function sprintf;
 
 /**
- * "JSON_CONTAINS" "(" StringPrimary "," StringPrimary ["," StringPrimary] ")"
+ * JsonContainsFunction ::= "JSON_CONTAINS" "(" StringPrimary "," StringPrimary ["," StringPrimary] ")"
+ *
+ * @link https://dev.mysql.com/doc/refman/en/json-search-functions.html#function_json-contains
+ *
+ * @example SELECT JSON_CONTAINS("{x: 2}", 2, "$.x")
+ * @example SELECT JSON_CONTAINS(foo.bar, "x", "$.bar") FROM entity
  */
 class JsonContains extends FunctionNode
 {
+    /** @var Node */
     protected $target;
 
+    /** @var Node */
     protected $candidate;
 
-    protected $path;
+    /** @var Node|null */
+    protected $path = null;
 
     public function parse(Parser $parser): void
     {
diff --git a/src/Query/Mysql/JsonDepth.php b/src/Query/Mysql/JsonDepth.php
index 47c97e38..3cee777e 100644
--- a/src/Query/Mysql/JsonDepth.php
+++ b/src/Query/Mysql/JsonDepth.php
@@ -3,6 +3,7 @@
 namespace DoctrineExtensions\Query\Mysql;
 
 use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
 use Doctrine\ORM\Query\Parser;
 use Doctrine\ORM\Query\SqlWalker;
 use Doctrine\ORM\Query\TokenType;
@@ -10,10 +11,15 @@
 use function sprintf;
 
 /**
- * "JSON_DEPTH" "(" StringPrimary ")"
+ * JsonDepthFunction ::= "JSON_DEPTH" "(" StringPrimary ")"
+ *
+ * @link https://dev.mysql.com/doc/refman/en/json-attribute-functions.html#function_json-depth
+ *
+ * @example SELECT JOIN_DEPTH(foo.bar) FROM entity
  */
 class JsonDepth extends FunctionNode
 {
+    /** @var Node */
     protected $target;
 
     public function parse(Parser $parser): void
diff --git a/src/Query/Mysql/JsonLength.php b/src/Query/Mysql/JsonLength.php
index d367aaea..1118e6c1 100644
--- a/src/Query/Mysql/JsonLength.php
+++ b/src/Query/Mysql/JsonLength.php
@@ -3,6 +3,7 @@
 namespace DoctrineExtensions\Query\Mysql;
 
 use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
 use Doctrine\ORM\Query\Parser;
 use Doctrine\ORM\Query\SqlWalker;
 use Doctrine\ORM\Query\TokenType;
@@ -10,13 +11,19 @@
 use function sprintf;
 
 /**
- * "JSON_LENGTH" "(" StringPrimary ["," StringPrimary] ")"
+ * JsonLengthFunction ::= "JSON_LENGTH" "(" StringPrimary ["," StringPrimary] ")"
+ *
+ * @link https://dev.mysql.com/doc/refman/en/json-attribute-functions.html#function_json-length
+ *
+ * @example SELECT JSON_LENGTH(foo.bar, "$.low") FROM entity
  */
 class JsonLength extends FunctionNode
 {
+    /** @var Node */
     protected $target;
 
-    protected $path;
+    /** @var Node|null */
+    protected $path = null;
 
     public function parse(Parser $parser): void
     {