From e243e8e547c0618005fd8cf71f0dc25d0d13b430 Mon Sep 17 00:00:00 2001
From: Andrea Piovanelli <83577153+AndreaPiovanelli@users.noreply.github.com>
Date: Thu, 11 Apr 2024 20:27:03 +0200
Subject: [PATCH] Incorrect NOLOCK position in queries where there is no table
 alias (#8783)

"WITH(NOLOCK)" is positioned before the where clause if there is no alias for the table.
---
 src/Orchard/Data/NoLockInterceptor.cs | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/Orchard/Data/NoLockInterceptor.cs b/src/Orchard/Data/NoLockInterceptor.cs
index 91da20f2c31..d06873b30ac 100644
--- a/src/Orchard/Data/NoLockInterceptor.cs
+++ b/src/Orchard/Data/NoLockInterceptor.cs
@@ -42,7 +42,7 @@ private string GetPrefixedTableName(string tableName) {
 
             return _shellSettings.DataTablePrefix + "_" + tableName;
         }
-        
+
         // based on https://stackoverflow.com/a/39518098/2669614
         public override SqlString OnPrepareStatement(SqlString sql) {
             // only work on select queries
@@ -167,7 +167,7 @@ public override SqlString OnPrepareStatement(SqlString sql) {
                         }
                     }
                     // rebuild query
-                    for(int i = 0; i < affectedCaptures.Count; i++) {
+                    for (int i = 0; i < affectedCaptures.Count; i++) {
                         var inner = affectedCaptures[i];
                         for (int j = i + 1; j < affectedCaptures.Count; j++) {
                             var outer = affectedCaptures[j];
@@ -203,7 +203,7 @@ public CaptureWrapper(Capture source, IEnumerable<string> tableNames) {
             public bool IsAltered { get; set; }
 
             public void AddNoLockHints() {
-                Value = AddNoLockHints(Value, TableNames); 
+                Value = AddNoLockHints(Value, TableNames);
             }
 
             private string AddNoLockHints(string query, IEnumerable<string> tableNames) {
@@ -240,13 +240,19 @@ private string AddNoLockHints(string query, IEnumerable<string> tableNames) {
                                 if (tableIndex == fromIndex + 1
                                     || parts[tableIndex - 1].Equals(",")) {
 
-                                    parts.Insert(tableIndex + 2, "WITH(NOLOCK)");
+                                    if (parts[tableIndex + 1].Equals("where", StringComparison.OrdinalIgnoreCase)) {
+                                        // There is no alias in the query, so we add "WITH(NOLOCK)" immediately after table name but before the "where" clause.
+                                        parts.Insert(tableIndex + 1, "WITH(NOLOCK)");
+                                    } else {
+                                        // We add "WITH(NOLOCK)" after the table alias.
+                                        parts.Insert(tableIndex + 2, "WITH(NOLOCK)");
+                                    }
                                 } else {
                                     // probably doing a join, so edit the next "on" and make it
                                     // "WITH (NOLOCK) on"
                                     for (int i = tableIndex + 1; i < whereIndex; i++) {
                                         if (parts[i].Trim().Equals("WITH(NOLOCK)", StringComparison.OrdinalIgnoreCase)) {
-                                            // we processed this table anme already
+                                            // we processed this table name already.
                                             break;
                                         }
                                         if (parts[i].Trim().Equals("on", StringComparison.OrdinalIgnoreCase)) {