From e6480a050c229917f84ff76737a0d77d84362d4e Mon Sep 17 00:00:00 2001
From: Kyle Brandt <kyle@grafana.com>
Date: Thu, 27 Mar 2025 16:49:21 -0400
Subject: [PATCH] SQL Expressions: Allow substring_index func (#103021)

---
 pkg/expr/sql/parser_allow.go      | 2 +-
 pkg/expr/sql/parser_allow_test.go | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkg/expr/sql/parser_allow.go b/pkg/expr/sql/parser_allow.go
index f19f1bc4e63..8d7b2d80e9e 100644
--- a/pkg/expr/sql/parser_allow.go
+++ b/pkg/expr/sql/parser_allow.go
@@ -189,7 +189,7 @@ func allowedFunction(f *sqlparser.FuncExpr) (b bool) {
 		return
 	case "lower", "upper":
 		return
-	case "substring":
+	case "substring", "substring_index":
 		return
 
 	// Date functions
diff --git a/pkg/expr/sql/parser_allow_test.go b/pkg/expr/sql/parser_allow_test.go
index 36aca7b0c27..6144c30f9d5 100644
--- a/pkg/expr/sql/parser_allow_test.go
+++ b/pkg/expr/sql/parser_allow_test.go
@@ -62,6 +62,11 @@ func TestAllowQuery(t *testing.T) {
 			q:    `SELECT 'some text' COLLATE utf8mb4_bin`,
 			err:  nil,
 		},
+		{
+			name: "allow substring_index",
+			q:    `SELECT __value__, SUBSTRING_INDEX(name, '.', -1) AS code FROM A`,
+			err:  nil,
+		},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {