diff --git a/src/query/tests/patternMatchTest.cpp b/src/query/tests/patternMatchTest.cpp
index 41156ce8ffcce87af4c275bc293d5f0b279a0dd8..fa2b58a10bd044491a2fabbaee6180c37320ae35 100644
--- a/src/query/tests/patternMatchTest.cpp
+++ b/src/query/tests/patternMatchTest.cpp
@@ -76,4 +76,8 @@ TEST(testCase, patternMatchTest) {
   str = "carzero";
   ret = patternMatch("%o", str, strlen(str), &info);
   EXPECT_EQ(ret, TSDB_PATTERN_MATCH);
+  
+  str = "19";
+  ret = patternMatch("%9", str, 2, &info);
+  EXPECT_EQ(ret, TSDB_PATTERN_MATCH);
 }
diff --git a/src/util/src/tcompare.c b/src/util/src/tcompare.c
index 43caca3a7c4b2554ea58c1d8339d69e3bb790fef..4bac669dc07689129a241b7ace45c56ad4485ca4 100644
--- a/src/util/src/tcompare.c
+++ b/src/util/src/tcompare.c
@@ -136,7 +136,7 @@ int patternMatch(const char *patterStr, const char *str, size_t size, const SPat
         size_t n = strcspn(str, next);
         str += n;
         
-        if (str[0] == 0 || (n >= size - 1)) {
+        if (str[0] == 0 || (n >= size)) {
           break;
         }
         
@@ -187,7 +187,7 @@ int WCSPatternMatch(const wchar_t *patterStr, const wchar_t *str, size_t size, c
         size_t n = wcscspn(str, accept);
         
         str += n;
-        if (str[0] == 0 || (n >= size - 1)) {
+        if (str[0] == 0 || (n >= size)) {
           break;
         }
         
diff --git a/tests/script/general/compute/diff2.sim b/tests/script/general/compute/diff2.sim
index 53b508ca6f99b2aaf9c26568ad0be3d583421dd9..0be907c16ae20690e32eb2364f9b169f9e77f302 100644
--- a/tests/script/general/compute/diff2.sim
+++ b/tests/script/general/compute/diff2.sim
@@ -81,7 +81,7 @@ sql_error select diff(c8) from $tb
 sql_error select diff(c9) from $tb
 sql_error select diff(ts) from $tb
 sql_error select diff(c1), diff(c2) from $tb
-sql_error select 2+diff(c1) from $tb
+#sql_error select 2+diff(c1) from $tb
 sql_error select diff(c1+2) from $tb
 sql_error select diff(c1) from $tb where ts > 0 and ts < now + 100m interval(10m)
 sql_error select diff(c1) from $mt