diff --git a/query/linkedql/registry_test.go b/query/linkedql/registry_test.go
index eec949a75..a385d4eef 100644
--- a/query/linkedql/registry_test.go
+++ b/query/linkedql/registry_test.go
@@ -93,7 +93,7 @@ var unmarshalCases = []struct {
 type TestStep struct {
 	Limit int        `json:"limit"`
 	Tags  []string   `json:"tags"`
-	From  PathStep   `json:"from"`
+	From  PathStep   `json:"from" minCardinality:"0"`
 	Sub   []PathStep `json:"sub"`
 }
 
diff --git a/query/linkedql/steps/as.go b/query/linkedql/steps/as.go
index 63642ccd9..919538d90 100644
--- a/query/linkedql/steps/as.go
+++ b/query/linkedql/steps/as.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*As)(nil)
 
 // As corresponds to .tag().
 type As struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	Name string            `json:"name"`
 }
 
diff --git a/query/linkedql/steps/back.go b/query/linkedql/steps/back.go
index ced6360a6..6c5753db2 100644
--- a/query/linkedql/steps/back.go
+++ b/query/linkedql/steps/back.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Back)(nil)
 
 // Back corresponds to .back().
 type Back struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	Name string            `json:"name"`
 }
 
diff --git a/query/linkedql/steps/both.go b/query/linkedql/steps/both.go
index 2d0d33c35..9fe1fb2d5 100644
--- a/query/linkedql/steps/both.go
+++ b/query/linkedql/steps/both.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Both)(nil)
 
 // Both corresponds to .both().
 type Both struct {
-	From       linkedql.PathStep     `json:"from"`
+	From       linkedql.PathStep     `json:"from" minCardinality:"0"`
 	Properties linkedql.PropertyPath `json:"properties"`
 }
 
diff --git a/query/linkedql/steps/context.go b/query/linkedql/steps/context.go
index 7384d04b1..02361d709 100644
--- a/query/linkedql/steps/context.go
+++ b/query/linkedql/steps/context.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Context)(nil)
 
 // Context corresponds to context().
 type Context struct {
-	From  linkedql.PathStep `json:"from"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
 	Rules map[string]string `json:"rules"`
 }
 
diff --git a/query/linkedql/steps/count.go b/query/linkedql/steps/count.go
index 33c378e6e..2cc2efc5f 100644
--- a/query/linkedql/steps/count.go
+++ b/query/linkedql/steps/count.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Count)(nil)
 
 // Count corresponds to .count().
 type Count struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/difference.go b/query/linkedql/steps/difference.go
index e4d10c14f..3d9811519 100644
--- a/query/linkedql/steps/difference.go
+++ b/query/linkedql/steps/difference.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Difference)(nil)
 
 // Difference corresponds to .difference().
 type Difference struct {
-	From  linkedql.PathStep   `json:"from"`
+	From  linkedql.PathStep   `json:"from" minCardinality:"0"`
 	Steps []linkedql.PathStep `json:"steps"`
 }
 
diff --git a/query/linkedql/steps/filter.go b/query/linkedql/steps/filter.go
index 985094f19..9267b6891 100644
--- a/query/linkedql/steps/filter.go
+++ b/query/linkedql/steps/filter.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Filter)(nil)
 
 // Filter corresponds to filter().
 type Filter struct {
-	From   linkedql.PathStep `json:"from"`
+	From   linkedql.PathStep `json:"from" minCardinality:"0"`
 	Filter linkedql.Operator `json:"filter"`
 }
 
diff --git a/query/linkedql/steps/follow.go b/query/linkedql/steps/follow.go
index 90b27a2de..1a644b9de 100644
--- a/query/linkedql/steps/follow.go
+++ b/query/linkedql/steps/follow.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Follow)(nil)
 
 // Follow corresponds to .follow().
 type Follow struct {
-	From     linkedql.PathStep `json:"from"`
+	From     linkedql.PathStep `json:"from" minCardinality:"0"`
 	Followed linkedql.PathStep `json:"followed"`
 }
 
diff --git a/query/linkedql/steps/follow_reverse.go b/query/linkedql/steps/follow_reverse.go
index 6e601c0b5..1026d4e1c 100644
--- a/query/linkedql/steps/follow_reverse.go
+++ b/query/linkedql/steps/follow_reverse.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*FollowReverse)(nil)
 
 // FollowReverse corresponds to .followR().
 type FollowReverse struct {
-	From     linkedql.PathStep `json:"from"`
+	From     linkedql.PathStep `json:"from" minCardinality:"0"`
 	Followed linkedql.PathStep `json:"followed"`
 }
 
diff --git a/query/linkedql/steps/greater_than.go b/query/linkedql/steps/greater_than.go
index 20d7e9ecf..f1f69a395 100644
--- a/query/linkedql/steps/greater_than.go
+++ b/query/linkedql/steps/greater_than.go
@@ -19,7 +19,7 @@ var _ linkedql.PathStep = (*GreaterThan)(nil)
 
 // GreaterThan corresponds to gt().
 type GreaterThan struct {
-	From  linkedql.PathStep `json:"from"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
 	Value quad.Value        `json:"value"`
 }
 
diff --git a/query/linkedql/steps/greater_than_equals.go b/query/linkedql/steps/greater_than_equals.go
index fb81c8c77..c51d540b1 100644
--- a/query/linkedql/steps/greater_than_equals.go
+++ b/query/linkedql/steps/greater_than_equals.go
@@ -19,7 +19,7 @@ var _ linkedql.PathStep = (*GreaterThanEquals)(nil)
 
 // GreaterThanEquals corresponds to gte().
 type GreaterThanEquals struct {
-	From  linkedql.PathStep `json:"from"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
 	Value quad.Value        `json:"value"`
 }
 
diff --git a/query/linkedql/steps/has.go b/query/linkedql/steps/has.go
index 683889c6f..2066dd47c 100644
--- a/query/linkedql/steps/has.go
+++ b/query/linkedql/steps/has.go
@@ -18,7 +18,7 @@ var _ linkedql.PathStep = (*Has)(nil)
 
 // Has corresponds to .has().
 type Has struct {
-	From     linkedql.PathStep     `json:"from"`
+	From     linkedql.PathStep     `json:"from" minCardinality:"0"`
 	Property linkedql.PropertyPath `json:"property"`
 	Values   []quad.Value          `json:"values"`
 }
diff --git a/query/linkedql/steps/has_reverse.go b/query/linkedql/steps/has_reverse.go
index 5ae1fae48..56fe37dd4 100644
--- a/query/linkedql/steps/has_reverse.go
+++ b/query/linkedql/steps/has_reverse.go
@@ -18,7 +18,7 @@ var _ linkedql.PathStep = (*HasReverse)(nil)
 
 // HasReverse corresponds to .hasR().
 type HasReverse struct {
-	From     linkedql.PathStep     `json:"from"`
+	From     linkedql.PathStep     `json:"from" minCardinality:"0"`
 	Property linkedql.PropertyPath `json:"property"`
 	Values   []quad.Value          `json:"values"`
 }
diff --git a/query/linkedql/steps/intersect.go b/query/linkedql/steps/intersect.go
index 69ad75246..f80dea39b 100644
--- a/query/linkedql/steps/intersect.go
+++ b/query/linkedql/steps/intersect.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Intersect)(nil)
 
 // Intersect represents .intersect() and .and().
 type Intersect struct {
-	From  linkedql.PathStep   `json:"from"`
+	From  linkedql.PathStep   `json:"from" minCardinality:"0"`
 	Steps []linkedql.PathStep `json:"steps"`
 }
 
diff --git a/query/linkedql/steps/is.go b/query/linkedql/steps/is.go
index 31ab8f284..c59353adf 100644
--- a/query/linkedql/steps/is.go
+++ b/query/linkedql/steps/is.go
@@ -18,7 +18,7 @@ var _ linkedql.PathStep = (*Is)(nil)
 
 // Is corresponds to .back().
 type Is struct {
-	From   linkedql.PathStep `json:"from"`
+	From   linkedql.PathStep `json:"from" minCardinality:"0"`
 	Values []quad.Value      `json:"values"`
 }
 
diff --git a/query/linkedql/steps/labels.go b/query/linkedql/steps/labels.go
index 51979ff7b..409b25813 100644
--- a/query/linkedql/steps/labels.go
+++ b/query/linkedql/steps/labels.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Labels)(nil)
 
 // Labels corresponds to .labels().
 type Labels struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/less_than.go b/query/linkedql/steps/less_than.go
index 395544990..bfbf87d9b 100644
--- a/query/linkedql/steps/less_than.go
+++ b/query/linkedql/steps/less_than.go
@@ -1,14 +1,13 @@
-
 package steps
 
 import (
 	"github.com/cayleygraph/cayley/graph"
 	"github.com/cayleygraph/cayley/graph/iterator"
 	"github.com/cayleygraph/cayley/query"
+	"github.com/cayleygraph/cayley/query/linkedql"
 	"github.com/cayleygraph/cayley/query/path"
 	"github.com/cayleygraph/quad"
 	"github.com/cayleygraph/quad/voc"
-	"github.com/cayleygraph/cayley/query/linkedql"
 )
 
 func init() {
@@ -20,13 +19,10 @@ var _ linkedql.PathStep = (*LessThan)(nil)
 
 // LessThan corresponds to lt().
 type LessThan struct {
-	From  linkedql.PathStep   `json:"from"`
-	Value quad.Value `json:"value"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
+	Value quad.Value        `json:"value"`
 }
 
-
-
-
 // Description implements Step.
 func (s *LessThan) Description() string {
 	return "Less than filters out values that are not less than given value"
@@ -45,4 +41,3 @@ func (s *LessThan) BuildPath(qs graph.QuadStore, ns *voc.Namespaces) (*path.Path
 	}
 	return fromPath.Filter(iterator.CompareLT, s.Value), nil
 }
-
diff --git a/query/linkedql/steps/less_than_equals.go b/query/linkedql/steps/less_than_equals.go
index c994cc8b5..b33d8d8ec 100644
--- a/query/linkedql/steps/less_than_equals.go
+++ b/query/linkedql/steps/less_than_equals.go
@@ -19,7 +19,7 @@ var _ linkedql.PathStep = (*LessThanEquals)(nil)
 
 // LessThanEquals corresponds to lte().
 type LessThanEquals struct {
-	From  linkedql.PathStep `json:"from"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
 	Value quad.Value        `json:"value"`
 }
 
diff --git a/query/linkedql/steps/limit.go b/query/linkedql/steps/limit.go
index 88b5ec630..e727ae450 100644
--- a/query/linkedql/steps/limit.go
+++ b/query/linkedql/steps/limit.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Limit)(nil)
 
 // Limit corresponds to .limit().
 type Limit struct {
-	From  linkedql.PathStep `json:"from"`
+	From  linkedql.PathStep `json:"from" minCardinality:"0"`
 	Limit int64             `json:"limit"`
 }
 
diff --git a/query/linkedql/steps/optional.go b/query/linkedql/steps/optional.go
index 0fe2fab8b..460179c8e 100644
--- a/query/linkedql/steps/optional.go
+++ b/query/linkedql/steps/optional.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Optional)(nil)
 
 // Optional corresponds to .optional().
 type Optional struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	Step linkedql.PathStep `json:"step"`
 }
 
diff --git a/query/linkedql/steps/order.go b/query/linkedql/steps/order.go
index 8e8824036..ce0591a79 100644
--- a/query/linkedql/steps/order.go
+++ b/query/linkedql/steps/order.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Order)(nil)
 
 // Order corresponds to .order().
 type Order struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/properties.go b/query/linkedql/steps/properties.go
index beb6c0959..ef9a1a469 100644
--- a/query/linkedql/steps/properties.go
+++ b/query/linkedql/steps/properties.go
@@ -18,7 +18,7 @@ var _ linkedql.PathStep = (*Properties)(nil)
 
 // Properties corresponds to .properties().
 type Properties struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	// TODO(iddan): Use linkedql.PropertyPath
 	Names []quad.IRI `json:"names"`
 }
diff --git a/query/linkedql/steps/property_names.go b/query/linkedql/steps/property_names.go
index f2abce564..5d7667d2c 100644
--- a/query/linkedql/steps/property_names.go
+++ b/query/linkedql/steps/property_names.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*PropertyNames)(nil)
 
 // PropertyNames corresponds to .propertyNames().
 type PropertyNames struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/property_names_as.go b/query/linkedql/steps/property_names_as.go
index 5f30ce40f..505993be2 100644
--- a/query/linkedql/steps/property_names_as.go
+++ b/query/linkedql/steps/property_names_as.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*PropertyNamesAs)(nil)
 
 // PropertyNamesAs corresponds to .propertyNamesAs().
 type PropertyNamesAs struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	Tag  string            `json:"tag"`
 }
 
diff --git a/query/linkedql/steps/reverse_properties.go b/query/linkedql/steps/reverse_properties.go
index 275b7f72c..c27f84619 100644
--- a/query/linkedql/steps/reverse_properties.go
+++ b/query/linkedql/steps/reverse_properties.go
@@ -18,7 +18,7 @@ var _ linkedql.PathStep = (*ReverseProperties)(nil)
 
 // ReverseProperties corresponds to .reverseProperties().
 type ReverseProperties struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	// TODO(iddan): Use property path
 	Names []quad.IRI `json:"names"`
 }
diff --git a/query/linkedql/steps/reverse_property_names.go b/query/linkedql/steps/reverse_property_names.go
index d107d0587..11542308c 100644
--- a/query/linkedql/steps/reverse_property_names.go
+++ b/query/linkedql/steps/reverse_property_names.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*ReversePropertyNames)(nil)
 
 // ReversePropertyNames corresponds to .reversePropertyNames().
 type ReversePropertyNames struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/reverse_property_names_as.go b/query/linkedql/steps/reverse_property_names_as.go
index a44a568ce..733982f32 100644
--- a/query/linkedql/steps/reverse_property_names_as.go
+++ b/query/linkedql/steps/reverse_property_names_as.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*ReversePropertyNamesAs)(nil)
 
 // ReversePropertyNamesAs corresponds to .reversePropertyNamesAs().
 type ReversePropertyNamesAs struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 	Tag  string            `json:"tag"`
 }
 
diff --git a/query/linkedql/steps/skip.go b/query/linkedql/steps/skip.go
index 8c47195c9..8cbbf8206 100644
--- a/query/linkedql/steps/skip.go
+++ b/query/linkedql/steps/skip.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Skip)(nil)
 
 // Skip corresponds to .skip().
 type Skip struct {
-	From   linkedql.PathStep `json:"from"`
+	From   linkedql.PathStep `json:"from" minCardinality:"0"`
 	Offset int64             `json:"offset"`
 }
 
diff --git a/query/linkedql/steps/steps_final.go b/query/linkedql/steps/steps_final.go
index 166600a7d..26f9a6d75 100644
--- a/query/linkedql/steps/steps_final.go
+++ b/query/linkedql/steps/steps_final.go
@@ -19,7 +19,7 @@ var _ linkedql.IteratorStep = (*Select)(nil)
 // Select corresponds to .select().
 type Select struct {
 	Tags []string          `json:"tags"`
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
@@ -41,7 +41,7 @@ var _ linkedql.IteratorStep = (*SelectFirst)(nil)
 // SelectFirst corresponds to .selectFirst().
 type SelectFirst struct {
 	Tags []string          `json:"tags"`
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
@@ -70,7 +70,7 @@ var _ linkedql.IteratorStep = (*Value)(nil)
 
 // Value corresponds to .value().
 type Value struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
@@ -87,7 +87,7 @@ var _ linkedql.IteratorStep = (*Documents)(nil)
 
 // Documents corresponds to .documents().
 type Documents struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/union.go b/query/linkedql/steps/union.go
index 57286081d..ae917ff9f 100644
--- a/query/linkedql/steps/union.go
+++ b/query/linkedql/steps/union.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Union)(nil)
 
 // Union corresponds to .union() and .or().
 type Union struct {
-	From  linkedql.PathStep   `json:"from"`
+	From  linkedql.PathStep   `json:"from" minCardinality:"0"`
 	Steps []linkedql.PathStep `json:"steps"`
 }
 
diff --git a/query/linkedql/steps/unique.go b/query/linkedql/steps/unique.go
index 4d21c72ea..7d25fd188 100644
--- a/query/linkedql/steps/unique.go
+++ b/query/linkedql/steps/unique.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Unique)(nil)
 
 // Unique corresponds to .unique().
 type Unique struct {
-	From linkedql.PathStep `json:"from"`
+	From linkedql.PathStep `json:"from" minCardinality:"0"`
 }
 
 // Description implements Step.
diff --git a/query/linkedql/steps/visit.go b/query/linkedql/steps/visit.go
index 559213f18..28842f212 100644
--- a/query/linkedql/steps/visit.go
+++ b/query/linkedql/steps/visit.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Visit)(nil)
 
 // Visit corresponds to .view().
 type Visit struct {
-	From       linkedql.PathStep     `json:"from"`
+	From       linkedql.PathStep     `json:"from" minCardinality:"0"`
 	Properties linkedql.PropertyPath `json:"properties"`
 }
 
diff --git a/query/linkedql/steps/visit_reverse.go b/query/linkedql/steps/visit_reverse.go
index c42cf4564..a16a224f9 100644
--- a/query/linkedql/steps/visit_reverse.go
+++ b/query/linkedql/steps/visit_reverse.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*VisitReverse)(nil)
 
 // VisitReverse corresponds to .viewReverse().
 type VisitReverse struct {
-	From       linkedql.PathStep     `json:"from"`
+	From       linkedql.PathStep     `json:"from" minCardinality:"0"`
 	Properties linkedql.PropertyPath `json:"properties"`
 }
 
diff --git a/query/linkedql/steps/where.go b/query/linkedql/steps/where.go
index 646be2f5a..5b8e0403e 100644
--- a/query/linkedql/steps/where.go
+++ b/query/linkedql/steps/where.go
@@ -17,7 +17,7 @@ var _ linkedql.PathStep = (*Where)(nil)
 
 // Where corresponds to .where().
 type Where struct {
-	From  linkedql.PathStep   `json:"from"`
+	From  linkedql.PathStep   `json:"from" minCardinality:"0"`
 	Steps []linkedql.PathStep `json:"steps"`
 }