DB.Query in Go
Query executes a query that returns rows, typically a SELECT. The args are for any placeholder parameters in the query.
package main
import "log"
func main() {
age := 27
q := `
create temp table uid (id bigint); -- Create temp table for queries.
insert into uid
select id from users where age < ?; -- Populate temp table.
-- First result set.
select
users.id, name
from
users
join uid on users.id = uid.id
;
-- Second result set.
select
ur.user, ur.role
from
user_roles as ur
join uid on uid.id = ur.user
;
`
rows, err := db.Query(q, age)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
for rows.Next() {
var (
id int64
name string
)
if err := rows.Scan(&id, &name); err != nil {
log.Fatal(err)
}
log.Printf("id %d name is %s\n", id, name)
}
if !rows.NextResultSet() {
log.Fatalf("expected more result sets: %v", rows.Err())
}
var roleMap = map[int64]string{
1: "user",
2: "admin",
3: "gopher",
}
for rows.Next() {
var (
id int64
role int64
)
if err := rows.Scan(&id, &role); err != nil {
log.Fatal(err)
}
log.Printf("id %d has role %s\n", id, roleMap[role])
}
if err := rows.Err(); err != nil {
log.Fatal(err)
}
}