Merge pull request #7765 from influxdata/js-7553-modulo-operator

Add modulo operator to the query language

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - [#7776](https://github.com/influxdata/influxdb/issues/7776): Add system information to /debug/vars.
 - [#7948](https://github.com/influxdata/influxdb/pull/7948): Reduce memory allocations by reusing gzip.Writers across requests
+- [#7553](https://github.com/influxdata/influxdb/issues/7553): Add modulo operator to the query language.
 
 ## v1.2.1 [unreleased]
 

influxql/ast.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"math"
 	"regexp"
 	"regexp/syntax"
 	"sort"
@@ -4301,6 +4302,11 @@ func evalBinaryExpr(expr *BinaryExpr, m map[string]interface{}) interface{} {
 				return float64(0)
 			}
 			return lhs / rhs
+		case MOD:
+			if !ok {
+				return nil
+			}
+			return math.Mod(lhs, rhs)
 		}
 	case int64:
 		// Try as a float64 to see if a float cast is required.
@@ -4332,6 +4338,8 @@ func evalBinaryExpr(expr *BinaryExpr, m map[string]interface{}) interface{} {
 					return float64(0)
 				}
 				return lhs / rhs
+			case MOD:
+				return math.Mod(lhs, rhs)
 			}
 		} else {
 			rhs, ok := rhs.(int64)
@@ -4370,6 +4378,13 @@ func evalBinaryExpr(expr *BinaryExpr, m map[string]interface{}) interface{} {
 					return float64(0)
 				}
 				return lhs / rhs
+			case MOD:
+				if !ok {
+					return nil
+				} else if rhs == 0 {
+					return int64(0)
+				}
+				return lhs % rhs
 			}
 		}
 	case string:
@@ -4709,6 +4724,11 @@ func reduceBinaryExprIntegerLHS(op Token, lhs *IntegerLiteral, rhs Expr) Expr {
 				return &NumberLiteral{Val: 0}
 			}
 			return &NumberLiteral{Val: float64(lhs.Val) / float64(rhs.Val)}
+		case MOD:
+			if rhs.Val == 0 {
+				return &IntegerLiteral{Val: 0}
+			}
+			return &IntegerLiteral{Val: lhs.Val % rhs.Val}
 		case EQ:
 			return &BooleanLiteral{Val: lhs.Val == rhs.Val}
 		case NEQ:
@@ -4775,6 +4795,8 @@ func reduceBinaryExprNumberLHS(op Token, lhs *NumberLiteral, rhs Expr) Expr {
 				return &NumberLiteral{Val: 0}
 			}
 			return &NumberLiteral{Val: lhs.Val / rhs.Val}
+		case MOD:
+			return &NumberLiteral{Val: math.Mod(lhs.Val, rhs.Val)}
 		case EQ:
 			return &BooleanLiteral{Val: lhs.Val == rhs.Val}
 		case NEQ:
@@ -4801,6 +4823,8 @@ func reduceBinaryExprNumberLHS(op Token, lhs *NumberLiteral, rhs Expr) Expr {
 				return &NumberLiteral{Val: 0}
 			}
 			return &NumberLiteral{Val: lhs.Val / float64(rhs.Val)}
+		case MOD:
+			return &NumberLiteral{Val: math.Mod(lhs.Val, float64(rhs.Val))}
 		case EQ:
 			return &BooleanLiteral{Val: lhs.Val == float64(rhs.Val)}
 		case NEQ:

influxql/ast_test.go

@@ -1175,6 +1175,10 @@ func TestReduce(t *testing.T) {
 		{in: `foo(bar(2 + 3), 4)`, out: `foo(bar(5), 4)`},
 		{in: `4 / 0`, out: `0.000`},
 		{in: `1 / 2`, out: `0.500`},
+		{in: `2 % 3`, out: `2`},
+		{in: `5 % 2`, out: `1`},
+		{in: `2 % 0`, out: `0`},
+		{in: `2.5 % 0`, out: `NaN`},
 		{in: `4 = 4`, out: `true`},
 		{in: `4 <> 4`, out: `false`},
 		{in: `6 > 4`, out: `true`},

influxql/scanner.go

@@ -65,6 +65,8 @@ func (s *Scanner) Scan() (tok Token, pos Pos, lit string) {
 		return MUL, pos, ""
 	case '/':
 		return DIV, pos, ""
+	case '%':
+		return MOD, pos, ""
 	case '=':
 		if ch1, _ := s.r.read(); ch1 == '~' {
 			return EQREGEX, pos, ""

influxql/scanner_test.go

@@ -34,6 +34,7 @@ func TestScanner_Scan(t *testing.T) {
 		{s: `-`, tok: influxql.SUB},
 		{s: `*`, tok: influxql.MUL},
 		{s: `/`, tok: influxql.DIV},
+		{s: `%`, tok: influxql.MOD},
 
 		// Logical operators
 		{s: `AND`, tok: influxql.AND},

influxql/select.go

@@ -3,6 +3,7 @@ package influxql
 import (
 	"errors"
 	"fmt"
+	"math"
 	"sort"
 	"time"
 )
@@ -1482,6 +1483,8 @@ func floatBinaryExprFunc(op Token) interface{} {
 			}
 			return lhs / rhs
 		}
+	case MOD:
+		return func(lhs, rhs float64) float64 { return math.Mod(lhs, rhs) }
 	case EQ:
 		return func(lhs, rhs float64) bool { return lhs == rhs }
 	case NEQ:
@@ -1513,6 +1516,13 @@ func integerBinaryExprFunc(op Token) interface{} {
 			}
 			return float64(lhs) / float64(rhs)
 		}
+	case MOD:
+		return func(lhs, rhs int64) int64 {
+			if rhs == 0 {
+				return int64(0)
+			}
+			return lhs % rhs
+		}
 	case EQ:
 		return func(lhs, rhs int64) bool { return lhs == rhs }
 	case NEQ:

influxql/token.go

@@ -36,6 +36,7 @@ const (
 	SUB // -
 	MUL // *
 	DIV // /
+	MOD // %
 
 	AND // AND
 	OR  // OR