diff --git a/expression/integration_test.go b/expression/integration_test.go
index 44292b944feea..9448546087076 100644
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -2035,10 +2035,14 @@ func (s *testIntegrationSuite) TestBuiltin(c *C) {
 	result.Check(testkit.Rows("<nil>"))
 	result = tk.MustQuery(`select cast(cast('2017-01-01 01:01:11.12' as date) as datetime(2));`)
 	result.Check(testkit.Rows("2017-01-01 00:00:00.00"))
-
 	result = tk.MustQuery(`select cast(20170118.999 as datetime);`)
 	result.Check(testkit.Rows("2017-01-18 00:00:00"))
 
+	tk.MustExec(`create table tb5(a bigint(64) unsigned, b double);`)
+	tk.MustExec(`insert into tb5 (a, b) values (9223372036854776000, 9223372036854776000);`)
+	tk.MustExec(`insert into tb5 (a, b) select * from (select cast(a as json) as a1, b from tb5) as t where t.a1 = t.b;`)
+	tk.MustExec(`drop table tb5;`)
+
 	// Test corner cases of cast string as datetime
 	result = tk.MustQuery(`select cast("170102034" as datetime);`)
 	result.Check(testkit.Rows("2017-01-02 03:04:00"))
diff --git a/types/convert.go b/types/convert.go
index fe0f1aaac93ff..42f2be4860214 100644
--- a/types/convert.go
+++ b/types/convert.go
@@ -523,8 +523,7 @@ func ConvertJSONToFloat(sc *stmtctx.StatementContext, j json.BinaryJSON) (float6
 	case json.TypeCodeInt64:
 		return float64(j.GetInt64()), nil
 	case json.TypeCodeUint64:
-		u, err := ConvertIntToUint(sc, j.GetInt64(), UnsignedUpperBound[mysql.TypeLonglong], mysql.TypeLonglong)
-		return float64(u), errors.Trace(err)
+		return float64(j.GetUint64()), nil
 	case json.TypeCodeFloat64:
 		return j.GetFloat64(), nil
 	case json.TypeCodeString:
diff --git a/types/convert_test.go b/types/convert_test.go
index 84836ac322238..19c8c786d6ce6 100644
--- a/types/convert_test.go
+++ b/types/convert_test.go
@@ -811,24 +811,26 @@ func (s *testTypeConvertSuite) TestConvertJSONToInt(c *C) {
 
 func (s *testTypeConvertSuite) TestConvertJSONToFloat(c *C) {
 	var tests = []struct {
-		In  string
+		In  interface{}
 		Out float64
+		ty  json.TypeCode
 	}{
-		{`{}`, 0},
-		{`[]`, 0},
-		{`3`, 3},
-		{`-3`, -3},
-		{`4.5`, 4.5},
-		{`true`, 1},
-		{`false`, 0},
-		{`null`, 0},
-		{`"hello"`, 0},
-		{`"123.456hello"`, 123.456},
-		{`"1234"`, 1234},
+		{make(map[string]interface{}, 0), 0, json.TypeCodeObject},
+		{make([]interface{}, 0), 0, json.TypeCodeArray},
+		{int64(3), 3, json.TypeCodeInt64},
+		{int64(-3), -3, json.TypeCodeInt64},
+		{uint64(1 << 63), 1 << 63, json.TypeCodeUint64},
+		{float64(4.5), 4.5, json.TypeCodeFloat64},
+		{true, 1, json.TypeCodeLiteral},
+		{false, 0, json.TypeCodeLiteral},
+		{nil, 0, json.TypeCodeLiteral},
+		{"hello", 0, json.TypeCodeString},
+		{"123.456hello", 123.456, json.TypeCodeString},
+		{"1234", 1234, json.TypeCodeString},
 	}
 	for _, tt := range tests {
-		j, err := json.ParseBinaryFromString(tt.In)
-		c.Assert(err, IsNil)
+		j := json.CreateBinary(tt.In)
+		c.Assert(j.TypeCode, Equals, tt.ty)
 		casted, _ := ConvertJSONToFloat(new(stmtctx.StatementContext), j)
 		c.Assert(casted, Equals, tt.Out)
 	}
diff --git a/types/datum_test.go b/types/datum_test.go
index a2d7a64739020..d41fb250dd571 100644
--- a/types/datum_test.go
+++ b/types/datum_test.go
@@ -218,6 +218,7 @@ func (ts *testDatumSuite) TestToJSON(c *C) {
 		{NewStringDatum("[1, 2, 3]"), `[1, 2, 3]`, true},
 		{NewStringDatum("{}"), `{}`, true},
 		{mustParseTimeIntoDatum("2011-11-10 11:11:11.111111", mysql.TypeTimestamp, 6), `"2011-11-10 11:11:11.111111"`, true},
+		{NewStringDatum(`{"a": "9223372036854775809"}`), `{"a": "9223372036854775809"}`, true},
 
 		// can not parse JSON from this string, so error occurs.
 		{NewStringDatum("hello, 世界"), "", false},