app/vmselect/promql: add the ability to copy all the labels from one side of group_left()/group_right() operation

This is performed by specifying `*` inside group_left()/group_right().
Also allow specifying prefix for the copied labels via `group_left(...) prefix "..."` and `group_right(...) prefix "..."` syntax.
For example, the following query adds all the namespace-related labels to pod info, and prefixes all the copied label names with "ns_" prefix:

  kube_pod_info * on(namespace) group_left(*) prefix "ns_" kube_namespace_labels

This resolves the following StackOverflow questions:

- https://stackoverflow.com/questions/76661818/how-to-add-namespace-labels-to-pod-labels-in-prometheus
- https://stackoverflow.com/questions/76653997/how-can-i-make-a-new-copy-of-kube-namespace-labels-metric-with-a-different-name

app/vmselect/promql/binary_op.go

@@ -225,6 +225,14 @@ func ensureSingleTimeseries(side string, be *metricsql.BinaryOpExpr, tss []*time
 
 func groupJoin(singleTimeseriesSide string, be *metricsql.BinaryOpExpr, rvsLeft, rvsRight, tssLeft, tssRight []*timeseries) ([]*timeseries, []*timeseries, error) {
 	joinTags := be.JoinModifier.Args
+	var skipTags []string
+	if strings.ToLower(be.GroupModifier.Op) == "on" {
+		skipTags = be.GroupModifier.Args
+	}
+	joinPrefix := ""
+	if be.JoinModifierPrefix != nil {
+		joinPrefix = be.JoinModifierPrefix.S
+	}
 	type tsPair struct {
 		left  *timeseries
 		right *timeseries
@@ -234,7 +242,7 @@ func groupJoin(singleTimeseriesSide string, be *metricsql.BinaryOpExpr, rvsLeft,
 		resetMetricGroupIfRequired(be, tsLeft)
 		if len(tssRight) == 1 {
 			// Easy case - right part contains only a single matching time series.
-			tsLeft.MetricName.SetTags(joinTags, &tssRight[0].MetricName)
+			tsLeft.MetricName.SetTags(joinTags, joinPrefix, skipTags, &tssRight[0].MetricName)
 			rvsLeft = append(rvsLeft, tsLeft)
 			rvsRight = append(rvsRight, tssRight[0])
 			continue
@@ -249,7 +257,7 @@ func groupJoin(singleTimeseriesSide string, be *metricsql.BinaryOpExpr, rvsLeft,
 		for _, tsRight := range tssRight {
 			var tsCopy timeseries
 			tsCopy.CopyFromShallowTimestamps(tsLeft)
-			tsCopy.MetricName.SetTags(joinTags, &tsRight.MetricName)
+			tsCopy.MetricName.SetTags(joinTags, joinPrefix, skipTags, &tsRight.MetricName)
 			bb.B = marshalMetricTagsSorted(bb.B[:0], &tsCopy.MetricName)
 			pair, ok := m[string(bb.B)]
 			if !ok {

app/vmselect/promql/exec_test.go

@@ -3575,6 +3575,102 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{r1, r2}
 		f(q, resultExpected)
 	})
+	t.Run(`vector + vector on group_left(*)`, func(t *testing.T) {
+		t.Parallel()
+		q := `sort_desc(
+			(label_set(time(), "t1", "v123", "t2", "v3"), label_set(10, "t2", "v3", "xxx", "yy"))
+			+ on (foo, t2) group_left (*)
+			(label_set(100, "t1", "v1"), label_set(time(), "t2", "v3", "noxxx", "aa"))
+		)`
+		r1 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{2000, 2400, 2800, 3200, 3600, 4000},
+			Timestamps: timestampsExpected,
+		}
+		r1.MetricName.Tags = []storage.Tag{
+			{
+				Key:   []byte("noxxx"),
+				Value: []byte("aa"),
+			},
+			{
+				Key:   []byte("t1"),
+				Value: []byte("v123"),
+			},
+			{
+				Key:   []byte("t2"),
+				Value: []byte("v3"),
+			},
+		}
+		r2 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1010, 1210, 1410, 1610, 1810, 2010},
+			Timestamps: timestampsExpected,
+		}
+		r2.MetricName.Tags = []storage.Tag{
+			{
+				Key:   []byte("noxxx"),
+				Value: []byte("aa"),
+			},
+			{
+				Key:   []byte("t2"),
+				Value: []byte("v3"),
+			},
+			{
+				Key:   []byte("xxx"),
+				Value: []byte("yy"),
+			},
+		}
+		resultExpected := []netstorage.Result{r1, r2}
+		f(q, resultExpected)
+	})
+	t.Run(`vector + vector on group_left(*) prefix`, func(t *testing.T) {
+		t.Parallel()
+		q := `sort_desc(
+			(label_set(time(), "t1", "v123", "t2", "v3"), label_set(10, "t2", "v3", "xxx", "yy"))
+			+ on (foo, t2) group_left (*) prefix "abc_"
+			(label_set(100, "t1", "v1"), label_set(time(), "t2", "v3", "noxxx", "aa"))
+		)`
+		r1 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{2000, 2400, 2800, 3200, 3600, 4000},
+			Timestamps: timestampsExpected,
+		}
+		r1.MetricName.Tags = []storage.Tag{
+			{
+				Key:   []byte("abc_noxxx"),
+				Value: []byte("aa"),
+			},
+			{
+				Key:   []byte("t1"),
+				Value: []byte("v123"),
+			},
+			{
+				Key:   []byte("t2"),
+				Value: []byte("v3"),
+			},
+		}
+		r2 := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1010, 1210, 1410, 1610, 1810, 2010},
+			Timestamps: timestampsExpected,
+		}
+		r2.MetricName.Tags = []storage.Tag{
+			{
+				Key:   []byte("abc_noxxx"),
+				Value: []byte("aa"),
+			},
+			{
+				Key:   []byte("t2"),
+				Value: []byte("v3"),
+			},
+			{
+				Key:   []byte("xxx"),
+				Value: []byte("yy"),
+			},
+		}
+		resultExpected := []netstorage.Result{r1, r2}
+		f(q, resultExpected)
+	})
 	t.Run(`vector + vector on group_left (__name__)`, func(t *testing.T) {
 		t.Parallel()
 		q := `sort_desc(

docs/CHANGELOG.md

@@ -30,6 +30,9 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * FEATURE: reduce memory usage by up to 5x for setups with [high churn rate](https://docs.victoriametrics.com/FAQ.html#what-is-high-churn-rate) and long [retention](https://docs.victoriametrics.com/#retention). See [description for this change](https://github.com/VictoriaMetrics/VictoriaMetrics/commit/7094fa38bc207c7bd7330ea8a834310a310ce5e3) for details.
 * FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): allow selecting time series matching at least one of multiple `or` filters. For example, `{env="prod",job="a" or env="dev",job="b"}` selects series with either `{env="prod",job="a"}` or `{env="dev",job="b"}` labels. This functionality allows passing the selected series to [rollup functions](https://docs.victoriametrics.com/MetricsQL.html#rollup-functions) without the need to use [subqueries](https://docs.victoriametrics.com/MetricsQL.html#subqueries). See [these docs](https://docs.victoriametrics.com/keyConcepts.html#filtering-by-multiple-or-filters).
 * FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): add ability to preserve metric names for binary operation results via `keep_metric_names` modifier. For example, `({__name__=~"foo|bar"} / 10) keep_metric_names` leaves `foo` and `bar` metric names in division results. See [these docs](https://docs.victoriametrics.com/MetricsQL.html#keep_metric_names). This helps to address issues like [this one](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3710).
+* FEATURE: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): add ability to copy all the labels from `one` side of [many-to-one operations](https://prometheus.io/docs/prometheus/latest/querying/operators/#many-to-one-and-one-to-many-vector-matches) by specifying `*` inside `group_left()` or `group_right()`. Also allow adding a prefix for copied label names via `group_left(*) prefix "..."` syntax. For example, the following query copies Kubernetes namespace labels to `kube_pod_info` series and adds `ns_` prefix for the copied label names: `kube_pod_info * on(namespace) group_left(*) prefix "ns_" kube_namespace_labels`. The labels from `on()` list aren't prefixed.
+  This feature resolves [this](https://stackoverflow.com/questions/76661818/how-to-add-namespace-labels-to-pod-labels-in-prometheus)
+  and [that](https://stackoverflow.com/questions/76653997/how-can-i-make-a-new-copy-of-kube-namespace-labels-metric-with-a-different-name) questions at StackOverflow.
 * FEATURE: [vmctl](https://docs.victoriametrics.com/vmctl.html): add verbose output for docker installations or when TTY isn't available. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4081).
 * FEATURE: [vmctl](https://docs.victoriametrics.com/vmctl.html): interrupt backoff retries when import process is cancelled. The change makes vmctl more responsive in case of errors during the import. See [this pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4442).
 * FEATURE: [vmctl](https://docs.victoriametrics.com/vmctl.html): update backoff policy on retries to reduce probability of overloading for `source` or `destination` databases. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4402).

docs/MetricsQL.md

@@ -56,7 +56,7 @@ Feel free [filing a feature request](https://github.com/VictoriaMetrics/Victoria
 This functionality can be evaluated at [VictoriaMetrics playground](https://play.victoriametrics.com/select/accounting/1/6a716b0f-38bc-4856-90ce-448fd713e3fe/prometheus/graph/)
 or at your own [VictoriaMetrics instance](https://docs.victoriametrics.com/#how-to-start-victoriametrics).
 
-The list of MetricsQL features:
+The list of MetricsQL features on top of PromQL:
 
 * Graphite-compatible filters can be passed via `{__graphite__="foo.*.bar"}` syntax.
   See [these docs](https://docs.victoriametrics.com/#selecting-graphite-metrics).
@@ -70,6 +70,13 @@ The list of MetricsQL features:
 * [Series selectors](https://docs.victoriametrics.com/keyConcepts.html#filtering) accept multiple `or` filters. For example, `{env="prod",job="a" or env="dev",job="b"}`
   selects series with either `{env="prod",job="a"}` or `{env="dev",job="b"}` labels.
   See [these docs](https://docs.victoriametrics.com/keyConcepts.html#filtering-by-multiple-or-filters) for details.
+* Support for `group_left(*)` and `group_right(*)` for copying all the labels from time series on the `one` side
+  of [many-to-one operations](https://prometheus.io/docs/prometheus/latest/querying/operators/#many-to-one-and-one-to-many-vector-matches).
+  The copied label names may clash with the existing label names, so MetricsQL provides an ability to add prefix to the copied metric names
+  via `group_left(*) prefix "..."` syntax.
+  For example, the following query copies all the `namespace`-related labels from `kube_namespace_labels` to `kube_pod_info` series,
+  while adding `ns_` prefix to the copied labels: `kube_pod_info * on(namespace) group_left(*) prefix "ns_" kube_namespace_labels`.
+  Labels from the `on()` list aren't copied.
 * [Aggregate functions](#aggregate-functions) accept arbitrary number of args.
   For example, `avg(q1, q2, q3)` would return the average values for every point across time series returned by `q1`, `q2` and `q3`.
 * [@ modifier](https://prometheus.io/docs/prometheus/latest/querying/basics/#modifier) can be put anywhere in the query.

go.mod

@@ -12,7 +12,7 @@ require (
 	// like https://github.com/valyala/fasthttp/commit/996610f021ff45fdc98c2ce7884d5fa4e7f9199b
 	github.com/VictoriaMetrics/fasthttp v1.2.0
 	github.com/VictoriaMetrics/metrics v1.24.0
-	github.com/VictoriaMetrics/metricsql v0.58.2
+	github.com/VictoriaMetrics/metricsql v0.59.0
 	github.com/aws/aws-sdk-go-v2 v1.18.1
 	github.com/aws/aws-sdk-go-v2/config v1.18.27
 	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.11.71

go.sum

@@ -69,8 +69,8 @@ github.com/VictoriaMetrics/fasthttp v1.2.0 h1:nd9Wng4DlNtaI27WlYh5mGXCJOmee/2c2b
 github.com/VictoriaMetrics/fasthttp v1.2.0/go.mod h1:zv5YSmasAoSyv8sBVexfArzFDIGGTN4TfCKAtAw7IfE=
 github.com/VictoriaMetrics/metrics v1.24.0 h1:ILavebReOjYctAGY5QU2F9X0MYvkcrG3aEn2RKa1Zkw=
 github.com/VictoriaMetrics/metrics v1.24.0/go.mod h1:eFT25kvsTidQFHb6U0oa0rTrDRdz4xTYjpL8+UPohys=
-github.com/VictoriaMetrics/metricsql v0.58.2 h1:xECDKK13ZR7LCpepVM7nuzJTnEkQI3r0qNxQIY6uv60=
+github.com/VictoriaMetrics/metricsql v0.59.0 h1:0kX7hSCcFFciVEOfoJsIkmlaLJkgoP/lmAsqlJTtTgg=
-github.com/VictoriaMetrics/metricsql v0.58.2/go.mod h1:k4UaP/+CjuZslIjd+kCigNG9TQmUqh5v0TP/nMEy90I=
+github.com/VictoriaMetrics/metricsql v0.59.0/go.mod h1:k4UaP/+CjuZslIjd+kCigNG9TQmUqh5v0TP/nMEy90I=
 github.com/VividCortex/ewma v1.2.0 h1:f58SaIzcDXrSy3kWaHNvuJgJ3Nmz59Zji6XoJR/q1ow=
 github.com/VividCortex/ewma v1.2.0/go.mod h1:nz4BbCtbLyFDeC9SUHbtcT5644juEuWfUAUnGx7j5l4=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=

lib/storage/metric_name.go

@@ -311,8 +311,20 @@ func (mn *MetricName) GetTagValue(tagKey string) []byte {
 }
 
 // SetTags sets tags from src with keys matching addTags.
-func (mn *MetricName) SetTags(addTags []string, src *MetricName) {
+//
+// It adds prefix to copied label names.
+// skipTags contains a list of tags, which must be skipped.
+func (mn *MetricName) SetTags(addTags []string, prefix string, skipTags []string, src *MetricName) {
+	if len(addTags) == 1 && addTags[0] == "*" {
+		// Special case for copying all the tags except of skipTags from src to mn.
+		mn.setAllTags(prefix, skipTags, src)
+		return
+	}
+	bb := bbPool.Get()
 	for _, tagName := range addTags {
+		if containsString(skipTags, tagName) {
+			continue
+		}
 		if tagName == string(metricGroupTagKey) {
 			mn.MetricGroup = append(mn.MetricGroup[:0], src.MetricGroup...)
 			continue
@@ -329,19 +341,47 @@ func (mn *MetricName) SetTags(addTags []string, src *MetricName) {
 			mn.RemoveTag(tagName)
 			continue
 		}
-		found := false
+		bb.B = append(bb.B[:0], prefix...)
-		for i := range mn.Tags {
+		bb.B = append(bb.B, tagName...)
-			t := &mn.Tags[i]
+		mn.SetTagBytes(bb.B, srcTag.Value)
-			if string(t.Key) == tagName {
+	}
-				t.Value = append(t.Value[:0], srcTag.Value...)
+	bbPool.Put(bb)
-				found = true
+}
-				break
+
-			}
+var bbPool bytesutil.ByteBufferPool
-		}
+
-		if !found {
+// SetTagBytes sets tag with the given key to the given value.
-			mn.AddTagBytes(srcTag.Key, srcTag.Value)
+func (mn *MetricName) SetTagBytes(key, value []byte) {
+	for i := range mn.Tags {
+		t := &mn.Tags[i]
+		if string(t.Key) == string(key) {
+			t.Value = append(t.Value[:0], value...)
+			return
 		}
 	}
+	mn.AddTagBytes(key, value)
+}
+
+func (mn *MetricName) setAllTags(prefix string, skipTags []string, src *MetricName) {
+	bb := bbPool.Get()
+	for _, tag := range src.Tags {
+		if containsString(skipTags, bytesutil.ToUnsafeString(tag.Key)) {
+			continue
+		}
+		bb.B = append(bb.B[:0], prefix...)
+		bb.B = append(bb.B, tag.Key...)
+		mn.SetTagBytes(bb.B, tag.Value)
+	}
+	bbPool.Put(bb)
+}
+
+func containsString(a []string, s string) bool {
+	for _, x := range a {
+		if x == s {
+			return true
+		}
+	}
+	return false
 }
 
 func hasTag(tags []string, key []byte) bool {

lib/storage/storage_test.go

@@ -1197,12 +1197,3 @@ func TestStorageDeleteStaleSnapshots(t *testing.T) {
 		t.Fatalf("cannot remove %q: %s", path, err)
 	}
 }
-
-func containsString(a []string, s string) bool {
-	for i := range a {
-		if a[i] == s {
-			return true
-		}
-	}
-	return false
-}

vendor/github.com/VictoriaMetrics/metricsql/parser.go

@@ -311,7 +311,7 @@ func (p *parser) parseWithArgExpr() (*withArgExpr, error) {
 	}
 	if p.lex.Token == "(" {
 		// Parse func args.
-		args, err := p.parseIdentList()
+		args, err := p.parseIdentList(false)
 		if err != nil {
 			return nil, fmt.Errorf(`withArgExpr: cannot parse args for %q: %s`, wa.Name, err)
 		}
@@ -365,16 +365,26 @@ func (p *parser) parseExpr() (Expr, error) {
 			}
 		}
 		if isBinaryOpGroupModifier(p.lex.Token) {
-			if err := p.parseModifierExpr(&be.GroupModifier); err != nil {
+			if err := p.parseModifierExpr(&be.GroupModifier, false); err != nil {
 				return nil, err
 			}
 			if isBinaryOpJoinModifier(p.lex.Token) {
 				if isBinaryOpLogicalSet(be.Op) {
 					return nil, fmt.Errorf(`modifier %q cannot be applied to %q`, p.lex.Token, be.Op)
 				}
-				if err := p.parseModifierExpr(&be.JoinModifier); err != nil {
+				if err := p.parseModifierExpr(&be.JoinModifier, true); err != nil {
 					return nil, err
 				}
+				if strings.ToLower(p.lex.Token) == "prefix" {
+					if err := p.lex.Next(); err != nil {
+						return nil, fmt.Errorf("cannot read prefix for %s: %w", be.JoinModifier.AppendString(nil), err)
+					}
+					se, err := p.parseStringExpr()
+					if err != nil {
+						return nil, fmt.Errorf("cannot parse prefix for %s: %w", be.JoinModifier.AppendString(nil), err)
+					}
+					be.JoinModifierPrefix = se
+				}
 			}
 		}
 		e2, err := p.parseSingleExpr()
@@ -608,7 +618,7 @@ funcPrefixLabel:
 		if !isAggrFuncModifier(p.lex.Token) {
 			return nil, fmt.Errorf(`AggrFuncExpr: unexpected token %q; want aggregate func modifier`, p.lex.Token)
 		}
-		if err := p.parseModifierExpr(&ae.Modifier); err != nil {
+		if err := p.parseModifierExpr(&ae.Modifier, false); err != nil {
 			return nil, err
 		}
 	}
@@ -623,7 +633,7 @@ funcArgsLabel:
 
 		// Verify whether func suffix exists.
 		if ae.Modifier.Op == "" && isAggrFuncModifier(p.lex.Token) {
-			if err := p.parseModifierExpr(&ae.Modifier); err != nil {
+			if err := p.parseModifierExpr(&ae.Modifier, false); err != nil {
 				return nil, err
 			}
 		}
@@ -665,6 +675,18 @@ func expandWithExpr(was []*withArgExpr, e Expr) (Expr, error) {
 		if err != nil {
 			return nil, err
 		}
+		var joinModifierPrefix *StringExpr
+		if t.JoinModifierPrefix != nil {
+			jmp, err := expandWithExpr(was, t.JoinModifierPrefix)
+			if err != nil {
+				return nil, err
+			}
+			se, ok := jmp.(*StringExpr)
+			if !ok {
+				return nil, fmt.Errorf("unexpected prefix for %s; want quoted string; got %s", t.JoinModifier.AppendString(nil), jmp.AppendString(nil))
+			}
+			joinModifierPrefix = se
+		}
 		if t.Op == "+" {
 			lse, lok := left.(*StringExpr)
 			rse, rok := right.(*StringExpr)
@@ -680,6 +702,7 @@ func expandWithExpr(was []*withArgExpr, e Expr) (Expr, error) {
 		be.Right = right
 		be.GroupModifier.Args = groupModifierArgs
 		be.JoinModifier.Args = joinModifierArgs
+		be.JoinModifierPrefix = joinModifierPrefix
 		pe := parensExpr{&be}
 		return &pe, nil
 	case *FuncExpr:
@@ -1084,7 +1107,7 @@ func isKeepMetricNames(token string) bool {
 	return token == "keep_metric_names"
 }
 
-func (p *parser) parseModifierExpr(me *ModifierExpr) error {
+func (p *parser) parseModifierExpr(me *ModifierExpr, allowStar bool) error {
 	if !isIdentPrefix(p.lex.Token) {
 		return fmt.Errorf(`ModifierExpr: unexpected token %q; want "ident"`, p.lex.Token)
 	}
@@ -1098,25 +1121,40 @@ func (p *parser) parseModifierExpr(me *ModifierExpr) error {
 		// join modifier may miss ident list.
 		return nil
 	}
-	args, err := p.parseIdentList()
+	args, err := p.parseIdentList(allowStar)
 	if err != nil {
-		return err
+		return fmt.Errorf("ModifierExpr: %w", err)
 	}
 	me.Args = args
 	return nil
 }
 
-func (p *parser) parseIdentList() ([]string, error) {
+func (p *parser) parseIdentList(allowStar bool) ([]string, error) {
 	if p.lex.Token != "(" {
 		return nil, fmt.Errorf(`identList: unexpected token %q; want "("`, p.lex.Token)
 	}
-	var idents []string
+	if err := p.lex.Next(); err != nil {
-	for {
+		return nil, err
+	}
+	if allowStar && p.lex.Token == "*" {
 		if err := p.lex.Next(); err != nil {
 			return nil, err
 		}
+		if p.lex.Token != ")" {
+			return nil, fmt.Errorf(`identList: unexpected token %q after "*"; want ")"`, p.lex.Token)
+		}
+		if err := p.lex.Next(); err != nil {
+			return nil, err
+		}
+		return []string{"*"}, nil
+	}
+	var idents []string
+	for {
 		if p.lex.Token == ")" {
-			goto closeParensLabel
+			if err := p.lex.Next(); err != nil {
+				return nil, err
+			}
+			return idents, nil
 		}
 		if !isIdentPrefix(p.lex.Token) {
 			return nil, fmt.Errorf(`identList: unexpected token %q; want "ident"`, p.lex.Token)
@@ -1127,19 +1165,15 @@ func (p *parser) parseIdentList() ([]string, error) {
 		}
 		switch p.lex.Token {
 		case ",":
-			continue
+			if err := p.lex.Next(); err != nil {
+				return nil, err
+			}
 		case ")":
-			goto closeParensLabel
+			continue
 		default:
 			return nil, fmt.Errorf(`identList: unexpected token %q; want ",", ")"`, p.lex.Token)
 		}
 	}
-
-closeParensLabel:
-	if err := p.lex.Next(); err != nil {
-		return nil, err
-	}
-	return idents, nil
 }
 
 func (p *parser) parseArgListExpr() ([]Expr, error) {
@@ -1628,6 +1662,11 @@ type BinaryOpExpr struct {
 	// JoinModifier contains modifier such as "group_left" or "group_right".
 	JoinModifier ModifierExpr
 
+	// JoinModifierPrefix is an optional prefix to add to labels specified inside group_left() or group_right() lists.
+	//
+	// The syntax is `group_left(foo,bar) prefix "abc"`
+	JoinModifierPrefix *StringExpr
+
 	// If KeepMetricNames is set to true, then the operation should keep metric names.
 	KeepMetricNames bool
 
@@ -1668,6 +1707,10 @@ func (be *BinaryOpExpr) appendStringNoKeepMetricNames(dst []byte) []byte {
 	if be.JoinModifier.Op != "" {
 		dst = append(dst, ' ')
 		dst = be.JoinModifier.AppendString(dst)
+		if prefix := be.JoinModifierPrefix; prefix != nil {
+			dst = append(dst, " prefix "...)
+			dst = prefix.AppendString(dst)
+		}
 	}
 	dst = append(dst, ' ')
 	if be.needRightParens() {
@@ -1739,7 +1782,11 @@ func (me *ModifierExpr) AppendString(dst []byte) []byte {
 	dst = append(dst, me.Op...)
 	dst = append(dst, '(')
 	for i, arg := range me.Args {
-		dst = appendEscapedIdent(dst, arg)
+		if arg == "*" {
+			dst = append(dst, '*')
+		} else {
+			dst = appendEscapedIdent(dst, arg)
+		}
 		if i+1 < len(me.Args) {
 			dst = append(dst, ',')
 		}

vendor/modules.txt

@@ -99,7 +99,7 @@ github.com/VictoriaMetrics/fasthttp/stackless
 # github.com/VictoriaMetrics/metrics v1.24.0
 ## explicit; go 1.20
 github.com/VictoriaMetrics/metrics
-# github.com/VictoriaMetrics/metricsql v0.58.2
+# github.com/VictoriaMetrics/metricsql v0.59.0
 ## explicit; go 1.13
 github.com/VictoriaMetrics/metricsql
 github.com/VictoriaMetrics/metricsql/binaryop