Merge pull request #132493 from cockroachdb/blathers/backport-release…

…-24.2-129711

release-24.2: opt: relax assertion for lookup join columns

pkg/sql/opt/memo/check_expr.go

@@ -222,11 +222,8 @@ func (m *Memo) CheckExpr(e opt.Expr) {
 		if t.Cols.SubsetOf(t.Input.Relational().OutputCols) {
 			panic(errors.AssertionFailedf("lookup join with no lookup columns"))
 		}
-		switch t.JoinType {
-		case opt.AntiJoinOp:
-			if len(t.RemoteLookupExpr) > 0 {
-				panic(errors.AssertionFailedf("anti join with a non-empty RemoteLookupExpr"))
-			}
+		if t.JoinType == opt.AntiJoinOp && len(t.RemoteLookupExpr) > 0 {
+			panic(errors.AssertionFailedf("anti join with a non-empty RemoteLookupExpr"))
 		}
 		var requiredCols opt.ColSet
 		requiredCols.UnionWith(t.Relational().OutputCols)
@@ -239,10 +236,17 @@ func (m *Memo) CheckExpr(e opt.Expr) {
 		for i := range t.KeyCols {
 			requiredCols.Add(t.Table.ColumnID(idx.Column(i).Ordinal()))
 		}
-		if !t.Cols.SubsetOf(requiredCols) {
+		projectedCols := t.Cols
+		if t.JoinType == opt.SemiJoinOp || t.JoinType == opt.AntiJoinOp {
+			// Semi and anti joins have an implicit projection that removes the
+			// columns from the right side. Therefore, we're not strict about removing
+			// right-side columns from t.Cols.
+			projectedCols = t.Cols.Intersection(t.Input.Relational().OutputCols)
+		}
+		if !projectedCols.SubsetOf(requiredCols) {
 			panic(errors.AssertionFailedf(
 				"lookup join with columns %s that are not required; required: %s",
-				t.Cols, requiredCols,
+				projectedCols, requiredCols,
 			))
 		}
 		if t.IsFirstJoinInPairedJoiner {