implement quote (#2973)

Author: jycor

enginetest/queries/queries.go

@@ -10146,7 +10146,6 @@ from typestable`,
 			{uint32(1000)},
 		},
 	},
-
 	{
 		Query: `select distinct pk1 from two_pk order by pk1`,
 		Expected: []sql.Row{
@@ -10255,14 +10254,12 @@ from typestable`,
 			{""},
 		},
 	},
-
 	{
 		Query: "select @@sql_mode = 1",
 		Expected: []sql.Row{
 			{false},
 		},
 	},
-
 	{
 		Query:            "explain select 1",
 		SkipServerEngine: true,
@@ -10290,6 +10287,20 @@ from typestable`,
 			{"     └─ name: "},
 		},
 	},
+	{
+		Query: "select quote(i), quote(s) from mytable",
+		Expected: []sql.Row{
+			{"'1'", "'first row'"},
+			{"'2'", "'second row'"},
+			{"'3'", "'third row'"},
+		},
+	},
+	{
+		Query: "select i, s from mytable where quote(i) = quote(2)",
+		Expected: []sql.Row{
+			{2, "second row"},
+		},
+	},
 }
 
 var KeylessQueries = []QueryTest{

sql/expression/function/registry.go

@@ -190,6 +190,7 @@ var BuiltIns = []sql.Function{
 	sql.Function2{Name: "pow", Fn: NewPower},
 	sql.Function2{Name: "power", Fn: NewPower},
 	sql.Function1{Name: "quarter", Fn: NewQuarter},
+	sql.Function1{Name: "quote", Fn: NewQuote},
 	sql.Function1{Name: "radians", Fn: NewRadians},
 	sql.FunctionN{Name: "rand", Fn: NewRand},
 	sql.FunctionN{Name: "regexp_instr", Fn: NewRegexpInstr},

sql/expression/function/string.go

@@ -15,6 +15,7 @@
 package function
 
 import (
+	"bytes"
 	"encoding/hex"
 	"fmt"
 	"math"
@@ -614,3 +615,55 @@ func (h *Bitlength) WithChildren(children ...sql.Expression) (sql.Expression, er
 	}
 	return NewBitlength(children[0]), nil
 }
+
+type Quote struct {
+	*UnaryFunc
+}
+
+var _ sql.FunctionExpression = (*Bitlength)(nil)
+var _ sql.CollationCoercible = (*Bitlength)(nil)
+
+func NewQuote(arg sql.Expression) sql.Expression {
+	return &Quote{UnaryFunc: NewUnaryFunc(arg, "QUOTE", types.Text)}
+}
+
+func (q *Quote) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
+	arg, err := q.EvalChild(ctx, row)
+	if err != nil {
+		return nil, err
+	}
+
+	val, _, err := types.Blob.Convert(ctx, arg)
+	if err != nil {
+		return nil, err
+	}
+	if val == nil {
+		return nil, nil
+	}
+	valBytes := val.([]byte)
+
+	ret := new(bytes.Buffer)
+	ret.WriteByte('\'')
+	for _, c := range valBytes {
+		switch c {
+		// '\032' is CTRL+Z character
+		case '\\', '\'', '\032':
+			ret.WriteByte('\\')
+			ret.WriteByte(c)
+		case '\000':
+			ret.WriteByte('\\')
+			ret.WriteByte('0')
+		default:
+			ret.WriteByte(c)
+		}
+	}
+	ret.WriteByte('\'')
+	return ret.String(), nil
+}
+
+func (q *Quote) WithChildren(children ...sql.Expression) (sql.Expression, error) {
+	if len(children) != 1 {
+		return nil, sql.ErrInvalidChildrenNumber.New(q, len(children), 1)
+	}
+	return NewQuote(children[0]), nil
+}

sql/expression/function/string_test.go

@@ -163,3 +163,15 @@ func TestBitLength(t *testing.T) {
 	tf.AddSucceeding(128, time.Now())
 	tf.Test(t, nil, nil)
 }
+
+func TestQuote(t *testing.T) {
+	f := sql.Function1{Name: "quote", Fn: NewQuote}
+	tf := NewTestFactory(f.Fn)
+	tf.AddSucceeding(nil, nil)
+	tf.AddSucceeding("'test'", "test")
+	tf.AddSucceeding("'0'", false)
+	tf.AddSucceeding("'1'", true)
+	tf.AddSucceeding("'12345'", 12345)
+	tf.AddSucceeding("'\\\\, \\', \\0, \\\032'", "\\, ', \000, \032")
+	tf.Test(t, nil, nil)
+}