From 82e54bda545e5a157b0c1a18fec2fbb28faaf511 Mon Sep 17 00:00:00 2001
From: Ren Hao <renh@sdkeji.com>
Date: Thu, 1 Aug 2019 09:12:20 +0800
Subject: [PATCH 1/2] Support decimal for sql execution.

---
 decimal.go   |  9 +++++++++
 packets.go   | 15 +++++++++++++++
 statement.go |  3 +++
 3 files changed, 27 insertions(+)
 create mode 100644 decimal.go

diff --git a/decimal.go b/decimal.go
new file mode 100644
index 000000000..b4015fa3c
--- /dev/null
+++ b/decimal.go
@@ -0,0 +1,9 @@
+package mysql
+
+import "database/sql/driver"
+
+type Decimal string
+
+func (d Decimal) Value() (driver.Value, error) {
+	return d, nil
+}
diff --git a/packets.go b/packets.go
index 30b3352c2..c3b21d63f 100644
--- a/packets.go
+++ b/packets.go
@@ -1102,6 +1102,21 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 					}
 				}
 
+			case Decimal:
+				paramTypes[i+i] = byte(fieldTypeNewDecimal)
+				paramTypes[i+i+1] = 0x00
+
+				if len(v) < longDataSize {
+					paramValues = appendLengthEncodedInteger(paramValues,
+						uint64(len(v)),
+					)
+					paramValues = append(paramValues, v...)
+				} else {
+					if err := stmt.writeCommandLongData(i, []byte(v)); err != nil {
+						return err
+					}
+				}
+
 			case time.Time:
 				paramTypes[i+i] = byte(fieldTypeString)
 				paramTypes[i+i+1] = 0x00
diff --git a/statement.go b/statement.go
index f7e370939..3b4845805 100644
--- a/statement.go
+++ b/statement.go
@@ -146,6 +146,9 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 		if err != nil {
 			return nil, err
 		}
+		if _, ok = sv.(Decimal); ok {
+			return sv, nil
+		}
 		if !driver.IsValue(sv) {
 			return nil, fmt.Errorf("non-Value type %T returned from Value", sv)
 		}

From e4cdc26b83521d9f768ab7f2b31d696441301b9c Mon Sep 17 00:00:00 2001
From: Ren Hao <renh@sdkeji.com>
Date: Thu, 15 Aug 2019 12:14:13 +0800
Subject: [PATCH 2/2] Update decimal type support.

---
 decimal.go   | 8 ++------
 packets.go   | 8 ++++----
 statement.go | 7 ++++---
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/decimal.go b/decimal.go
index b4015fa3c..d23023309 100644
--- a/decimal.go
+++ b/decimal.go
@@ -1,9 +1,5 @@
 package mysql
 
-import "database/sql/driver"
-
-type Decimal string
-
-func (d Decimal) Value() (driver.Value, error) {
-	return d, nil
+type Decimal interface {
+	DecimalString() string
 }
diff --git a/packets.go b/packets.go
index c3b21d63f..8b3197550 100644
--- a/packets.go
+++ b/packets.go
@@ -1106,13 +1106,13 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 				paramTypes[i+i] = byte(fieldTypeNewDecimal)
 				paramTypes[i+i+1] = 0x00
 
-				if len(v) < longDataSize {
+				if len(v.DecimalString()) < longDataSize {
 					paramValues = appendLengthEncodedInteger(paramValues,
-						uint64(len(v)),
+						uint64(len(v.DecimalString())),
 					)
-					paramValues = append(paramValues, v...)
+					paramValues = append(paramValues, v.DecimalString()...)
 				} else {
-					if err := stmt.writeCommandLongData(i, []byte(v)); err != nil {
+					if err := stmt.writeCommandLongData(i, []byte(v.DecimalString())); err != nil {
 						return err
 					}
 				}
diff --git a/statement.go b/statement.go
index 3b4845805..039cfafc9 100644
--- a/statement.go
+++ b/statement.go
@@ -141,14 +141,15 @@ func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
 		return v, nil
 	}
 
+	if _, ok := v.(Decimal); ok {
+		return v, nil
+	}
+
 	if vr, ok := v.(driver.Valuer); ok {
 		sv, err := callValuerValue(vr)
 		if err != nil {
 			return nil, err
 		}
-		if _, ok = sv.(Decimal); ok {
-			return sv, nil
-		}
 		if !driver.IsValue(sv) {
 			return nil, fmt.Errorf("non-Value type %T returned from Value", sv)
 		}