Map columns with enum keys are unsupported.

[leklund]

Map columns with enum keys are unsupported.

Queries that select map columns that use an enum key will fail and return an error:

Enum16('hello' = 1: invalid Enum

Steps to reproduce

1. Create a table with some data

CREATE TABLE map_test
(
  `data` Map(Enum16('hello' = 1, 'world' = 2), UInt64),
)
ENGINE = TinyLog;
INSERT INTO map_test(data) VALUES (map(1, 42, 2, 123));

2. Query:

sql := "SELECT data as Data FROM map_test"

var result []struct {
  Data map[string]uint64
}
if err := conn.Select(context.Background(), &result, sql); err != nil {
    fmt.Println(err)
}

fmt.Println(result)

3. Error:

Enum16('hello' = 1: invalid Enum

Expected behaviour

[{map[hello:42 world:123]}]

Cause

map.go is always splitting the type into two substrings on the first comma: https://github.com/ClickHouse/clickhouse-go/blob/main/lib/column/map.go#L69

In my examples case this string for t.params(): Enum16('hello' = 1, 'world' = 2), UInt64 will split into:

[]string{
  "Enum16('hello' = 1",
  " 'world' = 2), UInt64"
}

Configuration

Environment

• Client version: github.com/ClickHouse/clickhouse-go/v2 v2.20.0
• Language version: go1.21.2
• OS: Mac OS X darwin/arm64
• Interface: ClickHouse API

ClickHouse server

• ClickHouse Server version: 24.2.1.2248
• ClickHouse Server non-default settings, if any: none
• CREATE TABLE statements for tables involved: See above
• Sample data for all these tables: See above