diff --git a/pkg/sqlite/criterion_handlers.go b/pkg/sqlite/criterion_handlers.go
index c848f1a8b..6fe9c7ce9 100644
--- a/pkg/sqlite/criterion_handlers.go
+++ b/pkg/sqlite/criterion_handlers.go
@@ -1012,27 +1012,33 @@ func (h *stashIDCriterionHandler) handle(ctx context.Context, f *filterBuilder)
 		return
 	}
 
-	var stashIDs []*string
+	// ideally, this handler should just convert to stashIDsCriterionHandler
+	// but there are some differences in how the existing handler works compared
+	// to the new code, specifically because this code uses the stringCriterionHandler.
+	// To minimise potential regressions, we'll keep the existing logic for now.
+
+	stashIDRepo := h.stashIDRepository
+	t := stashIDRepo.tableName
+	if h.stashIDTableAs != "" {
+		t = h.stashIDTableAs
+	}
+
+	joinClause := fmt.Sprintf("%s.%s = %s", t, stashIDRepo.idColumn, h.parentIDCol)
+	if h.c.Endpoint != nil && *h.c.Endpoint != "" {
+		joinClause += fmt.Sprintf(" AND %s.endpoint = '%s'", t, *h.c.Endpoint)
+	}
+
+	f.addLeftJoin(stashIDRepo.tableName, h.stashIDTableAs, joinClause)
+
+	v := ""
 	if h.c.StashID != nil {
-		stashIDs = []*string{h.c.StashID}
-	} else {
-		stashIDs = nil
+		v = *h.c.StashID
 	}
 
-	convertedInput := &models.StashIDsCriterionInput{
-		Endpoint: h.c.Endpoint,
-		StashIDs: stashIDs,
+	stringCriterionHandler(&models.StringCriterionInput{
+		Value:    v,
 		Modifier: h.c.Modifier,
-	}
-
-	convertedHandler := stashIDsCriterionHandler{
-		c:                 convertedInput,
-		stashIDRepository: h.stashIDRepository,
-		stashIDTableAs:    h.stashIDTableAs,
-		parentIDCol:       h.parentIDCol,
-	}
-
-	convertedHandler.handle(ctx, f)
+	}, t+".stash_id")(ctx, f)
 }
 
 type stashIDsCriterionHandler struct {
@@ -1060,32 +1066,25 @@ func (h *stashIDsCriterionHandler) handle(ctx context.Context, f *filterBuilder)
 
 	f.addLeftJoin(stashIDRepo.tableName, h.stashIDTableAs, joinClause)
 
-	if len(h.c.StashIDs) == 0 {
-		stringCriterionHandler(&models.StringCriterionInput{
-			Value:    "",
-			Modifier: h.c.Modifier,
-		}, t+".stash_id")(ctx, f)
-	} else {
-		b := f
-		for _, n := range h.c.StashIDs {
-			query := &filterBuilder{}
-			v := ""
-			if n != nil {
-				v = *n
-			}
-
-			stringCriterionHandler(&models.StringCriterionInput{
-				Value:    v,
-				Modifier: h.c.Modifier,
-			}, t+".stash_id")(ctx, query)
-
-			if h.c.Modifier == models.CriterionModifierNotEquals {
-				b.and(query)
-			} else {
-				b.or(query)
-			}
-			b = query
+	switch h.c.Modifier {
+	case models.CriterionModifierIsNull:
+		f.addWhere(fmt.Sprintf("%s.stash_id IS NULL", t))
+	case models.CriterionModifierNotNull:
+		f.addWhere(fmt.Sprintf("%s.stash_id IS NOT NULL", t))
+	case models.CriterionModifierEquals:
+		var clauses []sqlClause
+		for _, id := range h.c.StashIDs {
+			clauses = append(clauses, makeClause(fmt.Sprintf("%s.stash_id = ?", t), id))
 		}
+		f.whereClauses = append(f.whereClauses, orClauses(clauses...))
+	case models.CriterionModifierNotEquals:
+		var clauses []sqlClause
+		for _, id := range h.c.StashIDs {
+			clauses = append(clauses, makeClause(fmt.Sprintf("%s.stash_id != ?", t), id))
+		}
+		f.whereClauses = append(f.whereClauses, andClauses(clauses...))
+	default:
+		f.setError(fmt.Errorf("invalid modifier %s for stash IDs criterion", h.c.Modifier))
 	}
 }
 
diff --git a/pkg/sqlite/sql.go b/pkg/sqlite/sql.go
index 2d5922555..0b55af8db 100644
--- a/pkg/sqlite/sql.go
+++ b/pkg/sqlite/sql.go
@@ -137,6 +137,8 @@ func getCountSort(primaryTable, joinTable, primaryFK, direction string) string {
 	return fmt.Sprintf(" ORDER BY (SELECT COUNT(*) FROM %s AS sort WHERE sort.%s = %s.id) %s", joinTable, primaryFK, primaryTable, getSortDirection(direction))
 }
 
+// getStringSearchClause returns a sqlClause for searching strings in the provided columns.
+// It is used for includes and excludes string criteria.
 func getStringSearchClause(columns []string, q string, not bool) sqlClause {
 	var likeClauses []string
 	var args []interface{}