Try to treat input values as enum id in tsv/scv

src/DataTypes/DataTypeEnum.cpp

@@ -155,7 +155,7 @@ void DataTypeEnum<Type>::deserializeTextEscaped(IColumn & column, ReadBuffer & i
         /// NOTE It would be nice to do without creating a temporary object - at least extract std::string out.
         std::string field_name;
         readEscapedString(field_name, istr);
-        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name)));
+        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name), true));
     }
 }
 
@@ -182,7 +182,7 @@ void DataTypeEnum<Type>::deserializeWholeText(IColumn & column, ReadBuffer & ist
     {
         std::string field_name;
         readString(field_name, istr);
-        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name)));
+        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name), true));
     }
 }
 
@@ -226,7 +226,7 @@ void DataTypeEnum<Type>::deserializeTextCSV(IColumn & column, ReadBuffer & istr,
     {
         std::string field_name;
         readCSVString(field_name, istr, settings.csv);
-        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name)));
+        assert_cast<ColumnType &>(column).getData().push_back(getValue(StringRef(field_name), true));
     }
 }
 

src/DataTypes/DataTypeEnum.h

@@ -4,6 +4,7 @@
 #include <Columns/ColumnVector.h>
 #include <Columns/ColumnConst.h>
 #include <Common/HashTable/HashMap.h>
+#include <IO/ReadHelpers.h>
 #include <vector>
 #include <unordered_map>
 
@@ -80,13 +81,25 @@ public:
         return findByValue(value)->second;
     }
 
-    FieldType getValue(StringRef field_name) const
+    FieldType getValue(StringRef field_name, bool try_treat_as_id=false) const
     {
-        const auto it = name_to_value_map.find(field_name);
-        if (!it)
+        const auto value_it = name_to_value_map.find(field_name);
+        if (!value_it)
+        {
+            /// It is used in CSV and TSV input formats. If we fail to find given string in
+            /// enum names and this string is number, we will try to treat it as enum id.
+            if (try_treat_as_id && isStringNumber(field_name))
+            {
+                FieldType x;
+                ReadBufferFromMemory tmp_buf(field_name.data, field_name.size);
+                readText(x, tmp_buf);
+                const auto name_it = value_to_name_map.find(x);
+                if (name_it != value_to_name_map.end())
+                    return x;
+            }
             throw Exception{"Unknown element '" + field_name.toString() + "' for type " + getName(), ErrorCodes::BAD_ARGUMENTS};
-
-        return it->getMapped();
+        }
+        return value_it->getMapped();
     }
 
     FieldType readValue(ReadBuffer & istr) const

src/IO/ReadHelpers.cpp

@@ -1111,4 +1111,12 @@ bool loadAtPosition(ReadBuffer & in, DB::Memory<> & memory, char * & current)
     return loaded_more;
 }
 
+bool isStringNumber(StringRef str)
+{
+    for (size_t i = 0; i != str.size; ++i)
+        if (!isdigit(str.data[i]))
+            return false;
+    return true;
+}
+
 }

src/IO/ReadHelpers.h

@@ -1228,4 +1228,6 @@ void saveUpToPosition(ReadBuffer & in, Memory<> & memory, char * current);
   */
 bool loadAtPosition(ReadBuffer & in, Memory<> & memory, char * & current);
 
+bool isStringNumber(StringRef str);
+
 }

tests/queries/0_stateless/01558_enum_as_num_in_tsv_csv_input.reference

@@ -0,0 +1,10 @@
+1	a
+2	3
+3	3
+4	a
+5	b
+6	a
+7	3
+8	3
+9	a
+10	b

tests/queries/0_stateless/01558_enum_as_num_in_tsv_csv_input.sql

@@ -0,0 +1,23 @@
+DROP TABLE IF EXISTS enum_as_num;
+
+CREATE TABLE enum_as_num (
+    Id Int32,
+    Value Enum('a' = 1, '3' = 2, 'b' = 3)
+) ENGINE=Memory();
+
+INSERT INTO enum_as_num FORMAT TSV 1	1
+INSERT INTO enum_as_num FORMAT TSV 2	2
+INSERT INTO enum_as_num FORMAT TSV 3	3
+INSERT INTO enum_as_num FORMAT TSV 4	a
+INSERT INTO enum_as_num FORMAT TSV 5	b
+
+INSERT INTO enum_as_num FORMAT CSV 6,1
+INSERT INTO enum_as_num FORMAT CSV 7,2
+INSERT INTO enum_as_num FORMAT CSV 8,3
+INSERT INTO enum_as_num FORMAT CSV 9,a
+INSERT INTO enum_as_num FORMAT CSV 10,b
+
+SELECT * FROM enum_as_num ORDER BY Id;
+
+
+DROP TABLE IF EXISTS enum_as_num;