From 28a61ef65fab83f9fc91af3c1f044921e7f07686 Mon Sep 17 00:00:00 2001
From: Takafumi Hirata <takhirata6@gmail.com>
Date: Wed, 10 Apr 2024 09:37:02 +0900
Subject: [PATCH] Implement unary minus operator

---
 internal/function_bind.go     | 18 ++++++++++++++++++
 internal/function_register.go |  1 +
 query_test.go                 | 21 ++++++++++++++++++++-
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/internal/function_bind.go b/internal/function_bind.go
index 2a11901..930d2c5 100644
--- a/internal/function_bind.go
+++ b/internal/function_bind.go
@@ -3,6 +3,7 @@ package internal
 import (
 	"errors"
 	"fmt"
+	"math"
 	"sync"
 
 	"github.com/goccy/go-json"
@@ -184,6 +185,23 @@ func bindOpDiv(args ...Value) (Value, error) {
 	return OP_DIV(args[0], args[1])
 }
 
+func bindUnaryMinus(args ...Value) (Value, error) {
+	if existsNull(args) {
+		return nil, nil
+	}
+	v, ok := args[0].(IntValue)
+	if ok {
+		i, err := v.ToInt64()
+		if err != nil {
+			return nil, err
+		}
+		if i <= math.MinInt64 {
+			return nil, fmt.Errorf("int64 overflow: -%d", i)
+		}
+	}
+	return SAFE_NEGATE(args[0])
+}
+
 func bindEqual(args ...Value) (Value, error) {
 	if existsNull(args) {
 		return nil, nil
diff --git a/internal/function_register.go b/internal/function_register.go
index fcbb58c..bf74c47 100644
--- a/internal/function_register.go
+++ b/internal/function_register.go
@@ -13,6 +13,7 @@ var normalFuncs = []*FuncInfo{
 	{Name: "subtract", BindFunc: bindSub},
 	{Name: "multiply", BindFunc: bindMul},
 	{Name: "divide", BindFunc: bindOpDiv},
+	{Name: "unary_minus", BindFunc: bindUnaryMinus},
 	{Name: "equal", BindFunc: bindEqual},
 	{Name: "not_equal", BindFunc: bindNotEqual},
 	{Name: "greater", BindFunc: bindGreater},
diff --git a/query_test.go b/query_test.go
index de6c697..4290a32 100644
--- a/query_test.go
+++ b/query_test.go
@@ -68,10 +68,29 @@ UNION ALL
 			expectedRows: [][]interface{}{{int64(1)}},
 		},
 		{
-			name:         "unary minus operator",
+			name:         "unary minus operator with literal",
 			query:        "SELECT -2",
 			expectedRows: [][]interface{}{{int64(-2)}},
 		},
+		{
+			name: "unary minus operator with column",
+			query: `WITH x AS (
+						SELECT 2 AS i, 2.0 AS f
+						UNION ALL
+						SELECT -9223372036854775807, -9223372036854775807
+						UNION ALL
+						SELECT NULL, -9223372036854775808
+					) SELECT -i, -f FROM x`,
+			expectedRows: [][]interface{}{
+				{int64(-2), float64(-2.0)},
+				{int64(9223372036854775807), float64(9223372036854775807)},
+				{nil, float64(9223372036854775808)}},
+		},
+		{
+			name:        "unary minus operator overflow",
+			query:       "WITH x AS (SELECT -9223372036854775808 as v) SELECT -v FROM x",
+			expectedErr: "int64 overflow: --9223372036854775808",
+		},
 		{
 			name:         "bit not operator",
 			query:        "SELECT ~1",