go/adbc/sqldriver: read from union types #2636
Description
What feature or improvement would you like to see?
It will be nice to support reading from union columns from databases that support them when using the database/sql adapter.
For example, in DuckDB, this should work:
// Register "duckdb" as described in https://pkg.go.dev/github.com/apache/arrow-adbc/go/adbc/sqldriver
// Error handling and closing resources omitted for brevity
db, err := sql.Open("duckdb", "")
_, err = db.Exec("create table test(a union(u varchar, v int))")
_, err = db.Exec("insert into test values('aba'),(2)")
rows, err := db.Query("select * from test")
for rows.Next() {
var s any
err = rows.Scan(&s)
fmt.Println(s)
}
if rows.Err() != nil {
fmt.Println(rows.Err())
}This should print:
aba
2
but currently prints:
Not Implemented: not yet implemented populating from columns of type sparse_union<u: type=utf8, nullable=0, v: type=int32, nullable=1>
I have a draft PR ready if the enhancement makes sense.