3 files changed, 35 insertions, 2 deletions
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 01fa1a6c2e9..5e470d59023 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1844,6 +1844,7 @@ typedef enum JsonTableColumnType
 	JTC_REGULAR,
 	JTC_EXISTS,
 	JTC_FORMATTED,
+	JTC_NESTED,
 } JsonTableColumnType;
 
 /*
@@ -1860,6 +1861,7 @@ typedef struct JsonTableColumn
 	JsonFormat *format;			/* JSON format clause, if specified */
 	JsonWrapper wrapper;		/* WRAPPER behavior for formatted columns */
 	JsonQuotes	quotes;			/* omit or keep quotes on scalar strings? */
+	List	   *columns;		/* nested columns */
 	JsonBehavior *on_empty;		/* ON EMPTY behavior */
 	JsonBehavior *on_error;		/* ON ERROR behavior */
 	int			location;		/* token location, or -1 if unknown */
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 6657f34103f..dafe93a4c95 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -1855,7 +1855,10 @@ typedef struct JsonTablePlan
 	NodeTag		type;
 } JsonTablePlan;
 
-/* JSON_TABLE plan to evaluate a JSON path expression */
+/*
+ * JSON_TABLE plan to evaluate a JSON path expression and NESTED paths, if
+ * any.
+ */
 typedef struct JsonTablePathScan
 {
 	JsonTablePlan plan;
@@ -1863,10 +1866,37 @@ typedef struct JsonTablePathScan
 	/* JSON path to evaluate */
 	JsonTablePath *path;
 
-	/* ERROR/EMPTY ON ERROR behavior */
+	/*
+	 * ERROR/EMPTY ON ERROR behavior; only significant in the plan for the
+	 * top-level path.
+	 */
 	bool		errorOnError;
+
+	/* Plan(s) for nested columns, if any. */
+	JsonTablePlan *child;
+
+	/*
+	 * 0-based index in TableFunc.colvalexprs of the 1st and the last column
+	 * covered by this plan.  Both are -1 if all columns are nested and thus
+	 * computed by the child plan(s).
+	 */
+	int			colMin;
+	int			colMax;
 } JsonTablePathScan;
 
+/*
+ * JsonTableSiblingJoin -
+ *		Plan to join rows of sibling NESTED COLUMNS clauses in the same parent
+ *		COLUMNS clause
+ */
+typedef struct JsonTableSiblingJoin
+{
+	JsonTablePlan plan;
+
+	JsonTablePlan *lplan;
+	JsonTablePlan *rplan;
+} JsonTableSiblingJoin;
+
 /* ----------------
  * NullTest
  *
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 9e4be53d93d..f9a4afd4723 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -286,6 +286,7 @@ PG_KEYWORD("names", NAMES, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("national", NATIONAL, COL_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("natural", NATURAL, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL)
 PG_KEYWORD("nchar", NCHAR, COL_NAME_KEYWORD, BARE_LABEL)
+PG_KEYWORD("nested", NESTED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("new", NEW, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("next", NEXT, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("nfc", NFC, UNRESERVED_KEYWORD, BARE_LABEL)