1) Now we support query filter of string implemented types.

2) We can pass commas to filter multiple values

query/builder.go

@@ -198,6 +198,9 @@ func (b *Builder) parseFilter(params url.Values) (string, []interface{}, error)
 		if !ok {
 			continue
 		}
+		if b.SplitValueOnComma && len(args) == 1 && strings.Contains(args[0], ",") {
+			args = strings.Split(args[0], ",")
+		}
 		// there are two expression formats:
 		// 1. "KEY = VAL"                     - when only one argument is given.
 		// 2. "(KEY = VAL OR KEY = VAL2 ...)" - when multiple values are given.
@@ -273,6 +276,9 @@ func (b *Builder) parseField(field *structs.Field) {
 	if contains(options, sortTag) {
 		b.sortFields[gorm.ToDBName(field.Name())] = true
 	}
+	if contains(options, splitTag) {
+		b.SplitValueOnComma = true
+	}
 	// struct field has a filter option.
 	if !contains(options, filterTag) {
 		return
@@ -310,10 +316,17 @@ func (b *Builder) parseField(field *structs.Field) {
 		b.addFilterField(withSep+opGreaterThanOrEqual, colName+" >= ?", parseFn)
 	default:
 		typ := reflect.TypeOf(v)
+		_, isStringer := v.(fmt.Stringer)
 		// add more cases if needed.
-		if typ.ConvertibleTo(reflect.TypeOf([]string{})) {
+		switch {
+		case typ.ConvertibleTo(reflect.TypeOf([]string{})):
 			b.addStringField(colName, withSep, wrapFn)
+		case isStringer:
+			b.addStringField(colName, withSep, wrapFn)
+		default:
+			panic(fmt.Sprintf("Could not use field %s (%T) with query filter", field.Name(), v))
 		}
+
 	}
 }
 

query/config.go

@@ -5,6 +5,7 @@ import "errors"
 const (
 	// fields in the struct tag.
 	sortTag   = "sort"
+	splitTag  = "split"
 	filterTag = "filter"
 	paramTag  = "param"
 	// search param in query string.
@@ -53,6 +54,8 @@ type Config struct {
 	OffsetParam string
 	// SearchOperator used to combine search condition together. defaults to "AND".
 	SearchOperator string
+	// SplitValueOnComma used to split the values on comma in the filter values in order to read multiple columns
+	SplitValueOnComma bool
 }
 
 func (c *Config) defaults() error {