fix #273

	add test cases
	comments use english more understandable

advisor/heuristic.go

@@ -133,16 +133,17 @@ func (q *Query4Audit) RuleEqualLike() Rule {
 			if strings.ToLower(expr.Operator) == "like" {
 				switch sqlval := expr.Right.(type) {
 				case *sqlparser.SQLVal:
-					// not start with '%', '_' && not end with '%', '_'
+					// 1. string that not contain '%', '_'
+					// 2. int, bit, float without wildcard
+					var hasWildCard bool
 					if sqlval.Type == 0 {
-						if sqlval.Val[0] != 0x25 &&
-							sqlval.Val[0] != 0x5f &&
-							sqlval.Val[len(sqlval.Val)-1] != 0x5f &&
-							sqlval.Val[len(sqlval.Val)-1] != 0x25 {
-							rule = HeuristicRules["ARG.002"]
-							return false, nil
+						for _, sqlElem := range sqlval.Val {
+							if sqlElem == 0x25 || sqlElem == 0x5f {
+								hasWildCard = true
 							}
-					} else {
+						}
+					}
+					if !hasWildCard {
 						rule = HeuristicRules["ARG.002"]
 						return false, nil
 					}

advisor/heuristic_test.go

@@ -132,11 +132,18 @@ func TestRulePrefixLike(t *testing.T) {
 // ARG.002
 func TestRuleEqualLike(t *testing.T) {
 	common.Log.Debug("Entering function: %s", common.GetFunctionName())
-	sqls := []string{
+	sqls := [][]string{
+		{
 			"select col from tbl where id like 'abc'",
 			"select col from tbl where id like 1",
+		},
+		{
+			"select col from tbl where id like 'abc%'",
+			"select col from tbl where id like '%abc'",
+			"select col from tbl where id like 'a%c'", // issue #273
+		},
 	}
-	for _, sql := range sqls {
+	for _, sql := range sqls[0] {
 		q, err := NewQuery4Audit(sql)
 		if err == nil {
 			rule := q.RuleEqualLike()
@@ -147,6 +154,19 @@ func TestRuleEqualLike(t *testing.T) {
 			t.Error("sqlparser.Parse Error:", err)
 		}
 	}
+
+	for _, sql := range sqls[1] {
+		q, err := NewQuery4Audit(sql)
+		if err == nil {
+			rule := q.RuleEqualLike()
+			if rule.Item == "ARG.002" {
+				t.Error("Rule not match:", rule.Item, "Expect : OK")
+			}
+		} else {
+			t.Error("sqlparser.Parse Error:", err)
+		}
+	}
+
 	common.Log.Debug("Exiting function: %s", common.GetFunctionName())
 }