Merge pull request #474 from pingcap/zimuxia/replace-func

Replace func

expression/builtin/builtin.go

@@ -100,6 +100,7 @@ var Funcs = map[string]Func{
 	"length":    {builtinLength, 1, 1, true, false},
 	"lower":     {builtinLower, 1, 1, true, false},
 	"repeat":    {builtinRepeat, 2, 2, true, false},
+	"replace":   {builtinReplace, 3, 3, true, false},
 	"upper":     {builtinUpper, 1, 1, true, false},
 
 	// information functions

expression/builtin/string.go

@@ -146,3 +146,27 @@ func builtinUpper(args []interface{}, ctx map[interface{}]interface{}) (interfac
 		return strings.ToUpper(s), nil
 	}
 }
+
+// See: https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_replace
+func builtinReplace(args []interface{}, ctx map[interface{}]interface{}) (interface{}, error) {
+	for _, arg := range args {
+		if types.IsNil(arg) {
+			return nil, nil
+		}
+	}
+
+	str, err := types.ToString(args[0])
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	oldStr, err := types.ToString(args[1])
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+	newStr, err := types.ToString(args[2])
+	if err != nil {
+		return nil, errors.Trace(err)
+	}
+
+	return strings.Replace(str, oldStr, newStr, -1), nil
+}

expression/builtin/string_test.go

@@ -166,3 +166,23 @@ func (s *testBuiltinSuite) TestLowerAndUpper(c *C) {
 		c.Assert(v, Equals, strings.ToUpper(t.Expect))
 	}
 }
+
+func (s *testBuiltinSuite) TestReplace(c *C) {
+	tbl := []struct {
+		Input  []interface{}
+		Expect interface{}
+	}{
+		{[]interface{}{nil, nil, nil}, nil},
+		{[]interface{}{1, nil, 2}, nil},
+		{[]interface{}{1, 1, nil}, nil},
+		{[]interface{}{"12345", 2, 222}, "1222345"},
+		{[]interface{}{"12325", 2, "a"}, "1a3a5"},
+		{[]interface{}{12345, 2, "aa"}, "1aa345"},
+	}
+
+	for _, t := range tbl {
+		v, err := builtinReplace(t.Input, nil)
+		c.Assert(err, IsNil)
+		c.Assert(v, Equals, t.Expect)
+	}
+}

expression/call.go

@@ -63,18 +63,18 @@ func NewCall(f string, args []Expression, distinct bool) (v Expression, err erro
 	}
 
 	c := Call{F: f, Distinct: distinct, distinctKey: new(int)}
-	for _, Val := range args {
-		if !Val.IsStatic() {
-			c.Args = append(c.Args, Val)
+	for _, val := range args {
+		if !val.IsStatic() {
+			c.Args = append(c.Args, val)
 			continue
 		}
 
-		eVal, err := Val.Eval(nil, nil)
+		v, err := val.Eval(nil, nil)
 		if err != nil {
 			return nil, err
 		}
 
-		c.Args = append(c.Args, Value{eVal})
+		c.Args = append(c.Args, Value{v})
 	}
 
 	return &c, nil

parser/parser.y

@@ -2439,6 +2439,19 @@ FunctionCallNonKeyword:
 			return 1
 		}
 	}
+|	"REPLACE" '(' Expression ',' Expression ',' Expression ')'
+	{
+		args := []expression.Expression{$3.(expression.Expression),
+						$5.(expression.Expression),
+						$7.(expression.Expression)}
+		var err error
+		$$, err = expression.NewCall($1.(string), args, false)
+		if err != nil {
+			l := yylex.(*lexer)
+			l.err(err)
+			return 1
+		}
+	}
 |	"SECOND" '(' Expression ')'
 	{
 		args := []expression.Expression{$3.(expression.Expression)}

parser/parser_test.go

@@ -349,6 +349,8 @@ func (s *testParserSuite) TestBuiltin(c *C) {
 
 		{`SELECT LOWER("A"), UPPER("a")`, true},
 
+		{`SELECT REPLACE('www.mysql.com', 'w', 'Ww')`, true},
+
 		{`SELECT LOCATE('bar', 'foobarbar');`, true},
 		{`SELECT LOCATE('bar', 'foobarbar', 5);`, true},
 

parser/scanner.l

@@ -816,7 +816,8 @@ year_month		{y}{e}{a}{r}_{m}{o}{n}{t}{h}
 			return repeat
 {regexp}		return regexp
 {references}		return references
-{replace}		return replace
+{replace}		lval.item = string(l.val)
+			return replace
 {rlike}			return rlike
 
 {sys_var}		lval.item = string(l.val)