From 9c438fe0e3710cc603e085f003948f2a5c63caf9 Mon Sep 17 00:00:00 2001
From: Yuanjia Zhang <zhangyuanjia@pingcap.com>
Date: Fri, 7 Feb 2020 14:02:52 +0800
Subject: [PATCH] expression: handle ErrTruncated when dividing decimals in
 non-data-change stmts (#14438)

---
 expression/builtin_arithmetic.go     | 3 +++
 expression/builtin_arithmetic_vec.go | 8 ++++++--
 expression/integration_test.go       | 9 ++++++++-
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/expression/builtin_arithmetic.go b/expression/builtin_arithmetic.go
index 03e0b448c111b..747d9fce0b05c 100644
--- a/expression/builtin_arithmetic.go
+++ b/expression/builtin_arithmetic.go
@@ -650,6 +650,9 @@ func (s *builtinArithmeticDivideDecimalSig) evalDecimal(row chunk.Row) (*types.M
 	err = types.DecimalDiv(a, b, c, types.DivFracIncr)
 	if err == types.ErrDivByZero {
 		return c, true, handleDivisionByZeroError(s.ctx)
+	} else if err == types.ErrTruncated {
+		sc := s.ctx.GetSessionVars().StmtCtx
+		err = sc.HandleTruncate(errTruncatedWrongValue.GenWithStackByArgs("DECIMAL", c))
 	} else if err == nil {
 		_, frac := c.PrecisionAndFrac()
 		if frac < s.baseBuiltinFunc.tp.Decimal {
diff --git a/expression/builtin_arithmetic_vec.go b/expression/builtin_arithmetic_vec.go
index e6d266df6feb3..954861d9e45be 100644
--- a/expression/builtin_arithmetic_vec.go
+++ b/expression/builtin_arithmetic_vec.go
@@ -79,6 +79,7 @@ func (b *builtinArithmeticDivideDecimalSig) vecEvalDecimal(input *chunk.Chunk, r
 	y := buf.Decimals()
 	var to types.MyDecimal
 	var frac int
+	sc := b.ctx.GetSessionVars().StmtCtx
 	for i := 0; i < n; i++ {
 		if result.IsNull(i) {
 			continue
@@ -90,6 +91,10 @@ func (b *builtinArithmeticDivideDecimalSig) vecEvalDecimal(input *chunk.Chunk, r
 			}
 			result.SetNull(i, true)
 			continue
+		} else if err == types.ErrTruncated {
+			if err = sc.HandleTruncate(errTruncatedWrongValue.GenWithStackByArgs("DECIMAL", to)); err != nil {
+				return err
+			}
 		} else if err == nil {
 			_, frac = to.PrecisionAndFrac()
 			if frac < b.baseBuiltinFunc.tp.Decimal {
@@ -698,8 +703,7 @@ func (b *builtinArithmeticIntDivideDecimalSig) vecEvalInt(input *chunk.Chunk, re
 		}
 		if err == types.ErrTruncated {
 			err = sc.HandleTruncate(errTruncatedWrongValue.GenWithStackByArgs("DECIMAL", c))
-		}
-		if err == types.ErrOverflow {
+		} else if err == types.ErrOverflow {
 			newErr := errTruncatedWrongValue.GenWithStackByArgs("DECIMAL", c)
 			err = sc.HandleOverflow(newErr, newErr)
 		}
diff --git a/expression/integration_test.go b/expression/integration_test.go
index 6ba5dfeb0ff15..ea05c6360b303 100755
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -3601,7 +3601,7 @@ func (s *testIntegrationSuite) TestAggregationBuiltinJSONObjectAgg(c *C) {
 		b varchar(100),
 		c decimal(3,2),
 		d json,
-		e date, 
+		e date,
 		f time,
 		g datetime DEFAULT '2012-01-01',
 		h timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
@@ -4438,6 +4438,13 @@ func (s *testIntegrationSuite) TestDecimalMul(c *C) {
 	res.Check(testkit.Rows("0.55125221922461136"))
 }
 
+func (s *testIntegrationSuite) TestDecimalDiv(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustQuery("select cast(1 as decimal(60,30)) / cast(1 as decimal(60,30)) / cast(1 as decimal(60, 30))").Check(testkit.Rows("1.000000000000000000000000000000"))
+	tk.MustQuery("select cast(1 as decimal(60,30)) / cast(3 as decimal(60,30)) / cast(7 as decimal(60, 30))").Check(testkit.Rows("0.047619047619047619047619047619"))
+	tk.MustQuery("select cast(1 as decimal(60,30)) / cast(3 as decimal(60,30)) / cast(7 as decimal(60, 30)) / cast(13 as decimal(60, 30))").Check(testkit.Rows("0.003663003663003663003663003663"))
+}
+
 func (s *testIntegrationSuite) TestUnknowHintIgnore(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("USE test")