1 // Copyright 2013 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package sql_test 6 7 import ( 8 "database/sql" 9 "fmt" 10 "log" 11 ) 12 13 var db *sql.DB 14 15 func ExampleDB_Query() { 16 age := 27 17 rows, err := db.Query("SELECT name FROM users WHERE age=?", age) 18 if err != nil { 19 log.Fatal(err) 20 } 21 defer rows.Close() 22 for rows.Next() { 23 var name string 24 if err := rows.Scan(&name); err != nil { 25 log.Fatal(err) 26 } 27 fmt.Printf("%s is %d\n", name, age) 28 } 29 if err := rows.Err(); err != nil { 30 log.Fatal(err) 31 } 32 } 33 34 func ExampleDB_QueryRow() { 35 id := 123 36 var username string 37 err := db.QueryRow("SELECT username FROM users WHERE id=?", id).Scan(&username) 38 switch { 39 case err == sql.ErrNoRows: 40 log.Printf("No user with that ID.") 41 case err != nil: 42 log.Fatal(err) 43 default: 44 fmt.Printf("Username is %s\n", username) 45 } 46 } 47 48 func ExampleDB_Query_multipleResultSets() { 49 age := 27 50 q := ` 51 create temp table uid (id bigint); -- Create temp table for queries. 52 insert into uid 53 select id from users where age < ?; -- Populate temp table. 54 55 -- First result set. 56 select 57 users.id, name 58 from 59 users 60 join uid on users.id = uid.id 61 ; 62 63 -- Second result set. 64 select 65 ur.user, ur.role 66 from 67 user_roles as ur 68 join uid on uid.id = ur.user 69 ; 70 ` 71 rows, err := db.Query(q, age) 72 if err != nil { 73 log.Fatal(err) 74 } 75 defer rows.Close() 76 77 for rows.Next() { 78 var ( 79 id int64 80 name string 81 ) 82 if err := rows.Scan(&id, &name); err != nil { 83 log.Fatal(err) 84 } 85 fmt.Printf("id %d name is %s\n", id, name) 86 } 87 if !rows.NextResultSet() { 88 log.Fatal("expected more result sets", rows.Err()) 89 } 90 var roleMap = map[int64]string{ 91 1: "user", 92 2: "admin", 93 3: "gopher", 94 } 95 for rows.Next() { 96 var ( 97 id int64 98 role int64 99 ) 100 if err := rows.Scan(&id, &role); err != nil { 101 log.Fatal(err) 102 } 103 fmt.Printf("id %d has role %s\n", id, roleMap[role]) 104 } 105 if err := rows.Err(); err != nil { 106 log.Fatal(err) 107 } 108 } 109
