*: Remove leading comment when check IsQuery

parser/parser_test.go

@@ -335,19 +335,21 @@ func (s *testParserSuite) TestParser0(c *C) {
 
 		// For select with where clause
 		{"SELECT * FROM t WHERE 1 = 1", true},
+
+		// For comment in query
+		{"/*comment*/ /*comment*/ select c /* this is a comment */ from t;", true},
 	}
 
 	for _, t := range table {
-		fmt.Printf("%s\n", t.src)
 		l := NewLexer(t.src)
 		ok := yyParse(l) == 0
 		c.Assert(ok, Equals, t.ok, Commentf("source %v", t.src))
 
 		switch ok {
 		case true:
-			c.Assert(len(l.errs), Equals, 0)
+			c.Assert(len(l.errs), Equals, 0, Commentf("src: %s", t.src))
 		case false:
-			c.Assert(len(l.errs), Not(Equals), 0)
+			c.Assert(len(l.errs), Not(Equals), 0, Commentf("src: %s", t.src))
 		}
 	}
 
@@ -391,4 +393,12 @@ func (s *testParserSuite) TestParser0(c *C) {
 	cv, ok := ss.Fields[0].Expr.(*expressions.FunctionCast)
 	c.Assert(ok, IsTrue)
 	c.Assert(cv.FunctionType, Equals, expressions.ConvertFunction)
+
+	// For query start with comment
+	src = "/* some comments */ /*comment*/ SELECT /*comment*/ CONVERT('111', /*comment*/ SIGNED) /*comment*/;"
+	l = NewLexer(src)
+	c.Assert(yyParse(l), Equals, 0)
+	st = l.Stmts()[0]
+	ss, ok = st.(*stmts.SelectStmt)
+	c.Assert(ok, IsTrue)
 }

tidb.go

@@ -243,9 +243,24 @@ func NewStore(uri string) (kv.Storage, error) {
 
 var queryStmtTable = []string{"explain", "select", "show", "execute", "describe", "desc"}
 
+func trimSQL(sql string) string {
+	// Trim space.
+	sql = strings.TrimSpace(sql)
+	// Trim leading /*comment*/
+	// There may be multiple comments
+	for strings.HasPrefix(sql, "/*") {
+		i := strings.Index(sql, "*/")
+		if i != -1 && i < len(sql)+1 {
+			sql = sql[i+2:]
+		}
+		sql = strings.TrimSpace(sql)
+	}
+	return sql
+}
+
 // IsQuery checks if a sql statement is a query statement.
 func IsQuery(sql string) bool {
-	sqlText := strings.ToLower(strings.TrimSpace(sql))
+	sqlText := strings.ToLower(trimSQL(sql))
 	for _, key := range queryStmtTable {
 		if strings.HasPrefix(sqlText, key) {
 			return true

tidb_test.go

@@ -292,6 +292,20 @@ func (s *testMainSuite) TestCheckArgs(c *C) {
 		"abc", []byte("abc"), time.Now(), time.Hour, time.Local)
 }
 
+func (s *testMainSuite) TestIsQuery(c *C) {
+	tbl := []struct {
+		sql string
+		ok  bool
+	}{
+		{"/*comment*/ select 1;", true},
+		{"/*comment*/ /*comment*/ select 1;", true},
+		{"select /*comment*/ 1 /*comment*/;", true},
+	}
+	for _, t := range tbl {
+		c.Assert(IsQuery(t.sql), Equals, t.ok, Commentf(t.sql))
+	}
+}
+
 func sessionExec(c *C, se Session, sql string) ([]rset.Recordset, error) {
 	se.Execute("BEGIN;")
 	r, err := se.Execute(sql)