diff --git a/expression/expression.go b/expression/expression.go
index 34ad4d60b1906..429ab2939dbbd 100644
--- a/expression/expression.go
+++ b/expression/expression.go
@@ -389,7 +389,7 @@ func toBool(sc *stmtctx.StatementContext, eType types.EvalType, buf *chunk.Colum
 			if buf.IsNull(i) {
 				isZero[i] = -1
 			} else {
-				if types.RoundFloat(f64s[i]) == 0 {
+				if f64s[i] == 0 {
 					isZero[i] = 0
 				} else {
 					isZero[i] = 1
@@ -444,11 +444,7 @@ func toBool(sc *stmtctx.StatementContext, eType types.EvalType, buf *chunk.Colum
 			if buf.IsNull(i) {
 				isZero[i] = -1
 			} else {
-				v, err := d64s[i].ToFloat64()
-				if err != nil {
-					return err
-				}
-				if types.RoundFloat(v) == 0 {
+				if d64s[i].IsZero() {
 					isZero[i] = 0
 				} else {
 					isZero[i] = 1
diff --git a/expression/integration_test.go b/expression/integration_test.go
index 8f7da00fe14d5..04e49235c9c49 100755
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -6187,6 +6187,15 @@ func (s *testIntegrationSuite) TestNegativeZeroForHashJoin(c *C) {
 	tk.MustExec("drop table t1;")
 }
 
+func (s *testIntegrationSuite) TestIssue15743(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t0")
+	tk.MustExec("CREATE TABLE t0(c0 int)")
+	tk.MustExec("INSERT INTO t0 VALUES (1)")
+	tk.MustQuery("SELECT * FROM t0 WHERE 1 AND 0.4").Check(testkit.Rows("1"))
+}
+
 func (s *testIntegrationSuite) TestIssue15725(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test;")
@@ -6241,3 +6250,15 @@ func (s *testIntegrationSuite) TestIssue16029(c *C) {
 	tk.MustExec("drop table t0;")
 	tk.MustExec("drop table t1;")
 }
+
+func (s *testIntegrationSuite) TestIssue16426(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t (a int)")
+	tk.MustExec("insert into t values (42)")
+	tk.MustQuery("select a from t where a/10000").Check(testkit.Rows("42"))
+	tk.MustQuery("select a from t where a/100000").Check(testkit.Rows("42"))
+	tk.MustQuery("select a from t where a/1000000").Check(testkit.Rows("42"))
+	tk.MustQuery("select a from t where a/10000000").Check(testkit.Rows("42"))
+}
diff --git a/types/datum.go b/types/datum.go
index 8b3167f5fc763..f4bf7f9e316d4 100644
--- a/types/datum.go
+++ b/types/datum.go
@@ -1434,9 +1434,9 @@ func (d *Datum) ToBool(sc *stmtctx.StatementContext) (int64, error) {
 	case KindUint64:
 		isZero = d.GetUint64() == 0
 	case KindFloat32:
-		isZero = RoundFloat(d.GetFloat64()) == 0
+		isZero = d.GetFloat64() == 0
 	case KindFloat64:
-		isZero = RoundFloat(d.GetFloat64()) == 0
+		isZero = d.GetFloat64() == 0
 	case KindString, KindBytes:
 		iVal, err1 := StrToFloat(sc, d.GetString())
 		isZero, err = iVal == 0, err1
@@ -1445,8 +1445,7 @@ func (d *Datum) ToBool(sc *stmtctx.StatementContext) (int64, error) {
 	case KindMysqlDuration:
 		isZero = d.GetMysqlDuration().Duration == 0
 	case KindMysqlDecimal:
-		v, err1 := d.GetMysqlDecimal().ToFloat64()
-		isZero, err = RoundFloat(v) == 0, err1
+		isZero = d.GetMysqlDecimal().IsZero()
 	case KindMysqlEnum:
 		isZero = d.GetMysqlEnum().ToNumber() == 0
 	case KindMysqlSet:
diff --git a/types/datum_test.go b/types/datum_test.go
index bba8e1900a9f0..2d7e3810739cb 100644
--- a/types/datum_test.go
+++ b/types/datum_test.go
@@ -67,10 +67,10 @@ func (ts *testDatumSuite) TestToBool(c *C) {
 	testDatumToBool(c, int(0), 0)
 	testDatumToBool(c, int64(0), 0)
 	testDatumToBool(c, uint64(0), 0)
-	testDatumToBool(c, float32(0.1), 0)
-	testDatumToBool(c, float64(0.1), 0)
+	testDatumToBool(c, float32(0.1), 1)
+	testDatumToBool(c, float64(0.1), 1)
 	testDatumToBool(c, float64(0.5), 1)
-	testDatumToBool(c, float64(0.499), 0)
+	testDatumToBool(c, float64(0.499), 1)
 	testDatumToBool(c, "", 0)
 	testDatumToBool(c, "0.1", 1)
 	testDatumToBool(c, []byte{}, 0)
@@ -91,7 +91,7 @@ func (ts *testDatumSuite) TestToBool(c *C) {
 	ft.Decimal = 5
 	v, err := Convert(0.1415926, ft)
 	c.Assert(err, IsNil)
-	testDatumToBool(c, v, 0)
+	testDatumToBool(c, v, 1)
 	d := NewDatum(&invalidMockType{})
 	sc := new(stmtctx.StatementContext)
 	sc.IgnoreTruncate = true