Remove code duplication and move utility methods to the store utils (#20091)

* Remove code duplication and move utility methods to the store utils

* Fix typo

store/sqlstore/utils_test.go

@@ -133,3 +133,30 @@ func TestMySQLJSONArgs(t *testing.T) {
 		assert.Equal(t, test.argString, argString)
 	}
 }
+
+func TestAppendMultipleStatementsFlag(t *testing.T) {
+	testCases := []struct {
+		Scenario    string
+		DSN         string
+		ExpectedDSN string
+	}{
+		{
+			"Should append multiStatements param to the DSN path with existing params",
+			"user:rand?&ompasswith@character@unix(/var/run/mysqld/mysqld.sock)/mattermost?writeTimeout=30s",
+			"user:rand?&ompasswith@character@unix(/var/run/mysqld/mysqld.sock)/mattermost?writeTimeout=30s&multiStatements=true",
+		},
+		{
+			"Should append multiStatements param to the DSN path with no existing params",
+			"user:rand?&ompasswith@character@unix(/var/run/mysqld/mysqld.sock)/mattermost",
+			"user:rand?&ompasswith@character@unix(/var/run/mysqld/mysqld.sock)/mattermost?multiStatements=true",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.Scenario, func(t *testing.T) {
+			res, err := AppendMultipleStatementsFlag(tc.DSN)
+			require.NoError(t, err)
+			assert.Equal(t, tc.ExpectedDSN, res)
+		})
+	}
+}