diff --git a/query_classifier/test/canonical_tests/canonizer.c b/query_classifier/test/canonical_tests/canonizer.c
index da06c998d..3f5de1e1a 100644
--- a/query_classifier/test/canonical_tests/canonizer.c
+++ b/query_classifier/test/canonical_tests/canonizer.c
@@ -57,8 +57,8 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    while (!feof(infile))
-    {
+	while (!feof(infile) && fgets(readbuff, 4092, infile))
+	{
         fgets(readbuff,4092,infile);
 		char* nl = strchr(readbuff, '\n');
 		if(nl)
diff --git a/query_classifier/test/canonical_tests/expected.sql b/query_classifier/test/canonical_tests/expected.sql
index b0a712096..8dab956e8 100644
--- a/query_classifier/test/canonical_tests/expected.sql
+++ b/query_classifier/test/canonical_tests/expected.sql
@@ -15,4 +15,78 @@ delete from tst where lname like '?' and fname like '?';
 select ? from tst where fname='?' or lname like '?';
 select ?,?,?,? from tst where name='?' or name='?' or name='?' or name='?';
 select count(?),count(?),count(?),count(?),count (?),count(?) from tst;
-select count(?),count(?),count(?),count(?),count (?),count(?) from tst;
+begin;
+BEGIN
+BEGIN;
+commit;
+COMMIT;
+COMMIT;
+CREATE DATABASE FOO;
+CREATE EVENT myevent
+CREATE FUNCTION hello (s CHAR(?))
+CREATE INDEX foo_t1 on T1 (id);
+CREATE PROCEDURE simpleproc (OUT param1 INT)
+CREATE TABLE myCity (a int, b char(?));
+create table t1 (id integer);
+create table t1(id integer);
+CREATE TABLE T1 (id integer);
+CREATE TABLE T1 (id integer);
+CREATE TABLE T2 (id integer);
+CREATE TEMPORARY TABLE T1 (id integer);
+DELETE FROM myCity;
+DELETE FROM myCity;
+DELIMITER ;//
+DELIMITER //;
+DO
+DROP DATABASE FOO;
+DROP DATABASE If EXISTS FOO;
+DROP EVENT IF EXISTS myevent;
+DROP EVENT myevent;
+DROP FUNCTION hello;
+DROP FUNCTION IF EXISTS hello;
+DROP PROCEDURE IF EXISTS simpleproc;
+DROP PROCEDURE simpleproc;
+DROP TABLE IF EXISTS myCity;
+drop table if exists t1;
+DROP TABLE IF EXISTS T1;
+DROP TABLE IF EXISTS T2;
+DROP TABLE myCity;
+drop table t1;
+DROP TABLE T1;
+DROP TABLE T2;
+END //
+INSERT INTO myCity VALUES (?, '?');
+INSERT INTO myCity VALUES (?, '?');
+insert into t1 values(?);
+insert into t1 values(?);
+INSERT INTO T2 VALUES (@@?);
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL ? HOUR
+RETURN CONCAT('?',s,'?');
+RETURNS CHAR(?) DETERMINISTIC
+SELECT @?;
+SELECT @?;
+SELECT COUNT(*) FROM myCity;
+select count(*) from t1;
+select count(*) from t1;
+select count(*) from user where user='?';
+    SELECT COUNT(*) INTO param1 FROM t;
+SELECT IF(@? <> @?,'?','?') AS result;
+SELECT IF(id <> @?,'?','?') AS result FROM T2;
+SELECT IF(@@? <> @?,'?','?') AS result;
+SELECT (@@?) INTO @?;
+set autocommit=?;
+SET autocommit=?;
+SET autocommit = ?;
+set autocommit=?;
+SET autocommit=?;
+SET AUTOCOMMIT=?;
+set autocommit=OFF;
+SET autocommit = oFf;
+SET autocommit = Off;
+SET AUTOCOMMIT=oN;
+START TRANSACTION;
+UPDATE t1 SET id = id + ?;
+use mysql;
+use test;
+USE test;
+USE test;
diff --git a/query_classifier/test/canonical_tests/input.sql b/query_classifier/test/canonical_tests/input.sql
index 59e9a2496..74c912212 100644
--- a/query_classifier/test/canonical_tests/input.sql
+++ b/query_classifier/test/canonical_tests/input.sql
@@ -15,3 +15,78 @@ delete from tst where lname like '%man%' and fname like '%ard%';
 select 100 from tst where fname='10' or lname like '%100%';
 select 1,20,300,4000 from tst where name='1000' or name='200' or name='30' or name='4';
 select count(1),count(10),count(100),count(2),count (20),count(200) from tst;
+begin;
+BEGIN
+BEGIN;
+commit;
+COMMIT;
+COMMIT;
+CREATE DATABASE FOO;
+CREATE EVENT myevent
+CREATE FUNCTION hello (s CHAR(20))
+CREATE INDEX foo_t1 on T1 (id);
+CREATE PROCEDURE simpleproc (OUT param1 INT)
+CREATE TABLE myCity (a int, b char(20));
+create table t1 (id integer);
+create table t1(id integer);
+CREATE TABLE T1 (id integer);
+CREATE TABLE T1 (id integer);
+CREATE TABLE T2 (id integer);
+CREATE TEMPORARY TABLE T1 (id integer);
+DELETE FROM myCity;
+DELETE FROM myCity;
+DELIMITER ;//
+DELIMITER //;
+DO
+DROP DATABASE FOO;
+DROP DATABASE If EXISTS FOO;
+DROP EVENT IF EXISTS myevent;
+DROP EVENT myevent;
+DROP FUNCTION hello;
+DROP FUNCTION IF EXISTS hello;
+DROP PROCEDURE IF EXISTS simpleproc;
+DROP PROCEDURE simpleproc;
+DROP TABLE IF EXISTS myCity;
+drop table if exists t1;
+DROP TABLE IF EXISTS T1;
+DROP TABLE IF EXISTS T2;
+DROP TABLE myCity;
+drop table t1;
+DROP TABLE T1;
+DROP TABLE T2;
+END //
+INSERT INTO myCity VALUES (1, 'Milan');
+INSERT INTO myCity VALUES (2, 'London');
+insert into t1 values(1);
+insert into t1 values(1);
+INSERT INTO T2 VALUES (@@server_id);
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR
+RETURN CONCAT('Hello, ',s,'!');
+RETURNS CHAR(50) DETERMINISTIC
+SELECT @a;
+SELECT @a;
+SELECT COUNT(*) FROM myCity;
+select count(*) from t1;
+select count(*) from t1;
+select count(*) from user where user='maxuser';
+    SELECT COUNT(*) INTO param1 FROM t;
+SELECT IF(@a <> @TMASTER_ID,'OK (slave)','FAIL (master)') AS result;
+SELECT IF(id <> @TMASTER_ID,'OK (slave)','FAIL (master)') AS result FROM T2;
+SELECT IF(@@server_id <> @TMASTER_ID,'OK (slave)','FAIL (master)') AS result;
+SELECT (@@server_id) INTO @a;
+set autocommit=0;
+SET autocommit=0;
+SET autocommit = 0;
+set autocommit=1;
+SET autocommit=1;
+SET AUTOCOMMIT=1;
+set autocommit=OFF;
+SET autocommit = oFf;
+SET autocommit = Off;
+SET AUTOCOMMIT=oN;
+START TRANSACTION;
+UPDATE t1 SET id = id + 1;
+use mysql;
+use test;
+USE test;
+USE test;
diff --git a/utils/skygw_utils.cc b/utils/skygw_utils.cc
index 56dc04d61..1b507a055 100644
--- a/utils/skygw_utils.cc
+++ b/utils/skygw_utils.cc
@@ -2033,7 +2033,8 @@ void skygw_file_close(
 
 
 static pcre2_code* replace_values_re = NULL;
-static const PCRE2_SPTR replace_values_pattern = (PCRE2_SPTR) "(?i)([-=,+*/([:space:]]|\\b)([0-9.]+|NULL)([-=,+*/)[:space:];]|$)";
+static const PCRE2_SPTR replace_values_pattern = (PCRE2_SPTR) "(?i)([-=,+*/([:space:]]|\\b|[@])"
+    "(?:[0-9.]+|(?<=[@])[a-z_]+|NULL)([-=,+*/)[:space:];]|$)";
 
 /**
  * Replace every literal number and NULL value with a question mark.
@@ -2042,7 +2043,7 @@ static const PCRE2_SPTR replace_values_pattern = (PCRE2_SPTR) "(?i)([-=,+*/([:sp
  */
 char* replace_values(const char* str)
 {
-    static const PCRE2_SPTR replace = (PCRE2_SPTR) "$1?$3";
+    static const PCRE2_SPTR replace = (PCRE2_SPTR) "$1?$2";
     pcre2_match_data* mdata;
     size_t orig_len = strlen(str);
     size_t len = orig_len;