Go 语言之 SQLX 高级操作 sqlx.In
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Go 语言之 SQLX 高级操作 sqlx.In
sqlx.In 介绍
sqlx is a package for Go which provides a set of extensions on top of the excellent built-in database/sql package.
Illustrated guide to SQLX：jmoiron.github.io/sqlx/
"In" Queries
Because database/sql does not inspect your query and it passes your arguments directly to the driver, it makes dealing with queries with IN clauses difficult:
SELECT * FROM users WHERE level IN (?);
When this gets prepared as a statement on the backend, the bindvar ? will only correspond to a single argument, but what is often desired is for that to be a variable number of arguments depending on the length of some slice, eg:
var levels = []int{4, 6, 7}rows, err := db.Query("SELECT * FROM users WHERE level IN (?);", levels)
This pattern is possible by first processing the query with sqlx.In:
var levels = []int{4, 6, 7}query, args, err := sqlx.In("SELECT * FROM users WHERE level IN (?);", levels) // sqlx.In returns queries with the `?` bindvar, we can rebind it for our backendquery = db.Rebind(query)rows, err := db.Query(query, args...)
What sqlx.In does is expand any bindvars in the query passed to it that correspond to a slice in the arguments to the length of that slice, and then append those slice elements to a new arglist. It does this with the ? bindvar only; you can use db.Rebind to get a query suitable for your backend.
普通批量插入数据，不使用 sqlx.In
package main
import (
"database/sql"
"fmt"
"strings"
"time"
_ "github.com/go-sql-driver/mysql" // 匿名导入 自动执行 init()
)
var db *sql.DB
func initMySQL() (err error) {
//DSN (Data Source Name)
dsn := "root:12345678@tcp(127.0.0.1:3306)/sql_test"
// 注意：要初始化全局的 db 对象，不要新声明一个 db 变量
db, err = sql.Open("mysql", dsn) // 只对格式进行校验，并不会真正连接数据库
if err != nil {
return err
}
// Ping 验证与数据库的连接是否仍处于活动状态，并在必要时建立连接。
err = db.Ping()
if err != nil {
fmt.Printf("connect to db failed, err: %v\n", err)
return err
}
// 数值需要根据业务具体情况来确定
db.SetConnMaxLifetime(time.Second * 10) // 设置可以重用连接的最长时间
db.SetConnMaxIdleTime(time.Second * 5) // 设置连接可能处于空闲状态的最长时间
db.SetMaxOpenConns(200) // 设置与数据库的最大打开连接数
db.SetMaxIdleConns(10) // 设置空闲连接池中的最大连接数
return nil
}
type User struct {
Name string `db:"name"`
Age int `db:"age"`
}
// BatchInsertUsers 批量插入数据
func BatchInsertUsers(users []*User) error {
valueStrings := make([]string, 0, len(users)) // 占位符 slice
valueArgs := make([]interface{}, 0, len(users)*2) // 插入值 slice
for _, u := range users {
valueStrings = append(valueStrings, "(?, ?)")
valueArgs = append(valueArgs, u.Name, u.Age) // 占位符与插入值 一一对应
}
// 拼接完整的SQL语句
// Sprintf根据格式说明符进行格式化，并返回结果字符串。
// Join将其第一个参数的元素连接起来以创建单个字符串。分隔字符串sep放置在结果字符串的元素之间。
stmt := fmt.Sprintf("INSERT INTO user (name, age) VALUES %s", strings.Join(valueStrings, ","))
// Exec执行查询而不返回任何行。参数用于查询中的任何占位符参数。
result, err := db.Exec(stmt, valueArgs...)
if err != nil {
fmt.Printf("Error inserting user into database: %v \n", err)
return err
}
var rows_affected int64
rows_affected, err = result.RowsAffected() // 返回受更新、插入或删除影响的行数。并非每个数据库或数据库驱动程序都支持此功能。
if err != nil {
fmt.Printf("返回受更新、插入或删除影响的行数 failed, err: %v\n", err)
return err
}
fmt.Println("受更新、插入或删除影响的行数: ", rows_affected)
return nil
}
func main() {
if err := initMySQL(); err != nil {
fmt.Printf("connect to db failed, err: %v\n", err)
}
// 检查完错误之后执行，确保 db 不为 nil
// Close() 用来释放数据库连接相关的资源
// Close 将关闭数据库并阻止启动新查询。关闭，然后等待服务器上已开始处理的所有查询完成。
defer db.Close()
fmt.Println("connect to database success")
// db.xx() 去使用数据库操作...
// 批量插入数据
users := []*User{
{Name: "刘备", Age: 25},
{Name: "关羽", Age: 30},
{Name: "张飞", Age: 28},
}
err := BatchInsertUsers(users)
if err != nil {
fmt.Printf("Failed to batch insert users: %v", err)
}
}
运行
Code/go/mysql_demo via 🐹 v1.20.3 via 🅒 base
➜ go run main.go
connect to database success
受更新、插入或删除影响的行数: 3
Code/go/mysql_demo via 🐹 v1.20.3 via 🅒 base
➜
SQL 查询结果
mysql> select * from user; # 插入之前
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
+----+--------+------+
11 rows in set (0.00 sec)
mysql> select * from user; # 插入之后
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
+----+--------+------+
14 rows in set (0.01 sec)
使用 sqlx.In 批量插入
package main
import (
"database/sql/driver"
"fmt"
_ "github.com/go-sql-driver/mysql"
"github.com/jmoiron/sqlx"
)
var db *sqlx.DB
func initDB() (err error) {
dsn := "root:12345678@tcp(127.0.0.1:3306)/sql_test?charset=utf8mb4&parseTime=True"
// 连接到数据库并使用ping进行验证。
// 也可以使用 MustConnect MustConnect连接到数据库，并在出现错误时恐慌 panic。
db, err = sqlx.Connect("mysql", dsn)
if err != nil {
fmt.Printf("connect DB failed, err:%v\n", err)
return
}
db.SetMaxOpenConns(20) // 设置数据库的最大打开连接数。
db.SetMaxIdleConns(10) // 设置空闲连接池中的最大连接数。
return
}
type user struct {
ID int `db:"id"`
Age int `db:"age"`
Name string `db:"name"`
}
func (u user) Value() (driver.Value, error) {
return []interface{}{u.Name, u.Age}, nil
}
// BatchInsertUsersSqlxIn 使用sqlx.In帮我们拼接语句和参数, 注意传入的参数是[]interface{}
func BatchInsertUsersSqlxIn(users []interface{}) error {
// In展开args中的切片值，返回修改后的查询字符串和一个可以由数据库执行的新的arg列表。
// “查询”应该使用“?”“bindVar。返回值使用' ?“bindVar。
query, args, _ := sqlx.In(
"INSERT INTO user (name, age) VALUES (?), (?), (?)",
users..., // 如果arg实现了 driver.Valuer, sqlx.In 会通过调用 Value()来展开它
)
fmt.Println("query sql string: ", query) // 查看生成的querystring
fmt.Println("args: ", args) // 查看生成的args
// Exec执行查询而不返回任何行。参数用于查询中的任何占位符参数。
result, err := db.Exec(query, args...)
var rows_affected int64
rows_affected, err = result.RowsAffected() // 返回受更新、插入或删除影响的行数。并非每个数据库或数据库驱动程序都支持此功能。
if err != nil {
fmt.Printf("返回受更新、插入或删除影响的行数 failed, err: %v\n", err)
return err
}
fmt.Println("受更新、插入或删除影响的行数: ", rows_affected)
return nil
}
func main() {
if err := initDB(); err != nil {
fmt.Printf("init DB failed, err:%v\n", err)
return
}
fmt.Println("init DB succeeded")
// 批量插入
u1 := user{Name: "李白", Age: 16}
u2 := user{Name: "杜甫", Age: 42}
u3 := user{Name: "王维", Age: 29}
users := []interface{}{u1, u2, u3}
_ = BatchInsertUsersSqlxIn(users)
}
运行
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜ go run main.go
init DB succeeded
query sql string: INSERT INTO user (name, age) VALUES (?, ?), (?, ?), (?, ?)
args: [李白 16 杜甫 42 王维 29]
受更新、插入或删除影响的行数: 3
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
SQL 查询结果
mysql> select * from user;
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
+----+--------+------+
14 rows in set (0.01 sec)
mysql> select * from user; # 插入之后
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
| 18 | 李白 | 16 |
| 19 | 杜甫 | 42 |
| 20 | 王维 | 29 |
+----+--------+------+
17 rows in set (0.00 sec)
mysql>
使用 NamedExec 批量插入
package main
import (
"database/sql/driver"
"fmt"
_ "github.com/go-sql-driver/mysql"
"github.com/jmoiron/sqlx"
)
var db *sqlx.DB
func initDB() (err error) {
dsn := "root:12345678@tcp(127.0.0.1:3306)/sql_test?charset=utf8mb4&parseTime=True"
// 连接到数据库并使用ping进行验证。
// 也可以使用 MustConnect MustConnect连接到数据库，并在出现错误时恐慌 panic。
db, err = sqlx.Connect("mysql", dsn)
if err != nil {
fmt.Printf("connect DB failed, err:%v\n", err)
return
}
db.SetMaxOpenConns(20) // 设置数据库的最大打开连接数。
db.SetMaxIdleConns(10) // 设置空闲连接池中的最大连接数。
return
}
type user struct {
ID int `db:"id"`
Age int `db:"age"`
Name string `db:"name"`
}
func (u user) Value() (driver.Value, error) {
return []interface{}{u.Name, u.Age}, nil
}
// BatchInsertUsersNamedExec NamedExec 批量插入
func BatchInsertUsersNamedExec(users []*user) error {
// 任何命名的占位符参数都将被arg中的字段替换。
result, err := db.NamedExec("INSERT INTO user (name, age) VALUES (:name, :age)", users)
var rows_affected int64
rows_affected, err = result.RowsAffected() // 返回受更新、插入或删除影响的行数。并非每个数据库或数据库驱动程序都支持此功能。
if err != nil {
fmt.Printf("返回受更新、插入或删除影响的行数 failed, err: %v\n", err)
return err
}
fmt.Println("BatchInsertUsersNamedExec 受插入影响的行数: ", rows_affected)
return nil
}
func main() {
if err := initDB(); err != nil {
fmt.Printf("init DB failed, err:%v\n", err)
return
}
fmt.Println("init DB succeeded")
// 批量插入
u1 := user{Name: "褒姒", Age: 16}
u2 := user{Name: "貂蝉", Age: 42}
u3 := user{Name: "飞燕", Age: 29}
// NamedExec
users := []*user{&u1, &u2, &u3}
_ = BatchInsertUsersNamedExec(users)
}
运行
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜ go run main.go
init DB succeeded
BatchInsertUsersNamedExec 受插入影响的行数: 3
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜
SQL 查询结果
mysql> select * from user;
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
| 18 | 李白 | 16 |
| 19 | 杜甫 | 42 |
| 20 | 王维 | 29 |
+----+--------+------+
17 rows in set (0.00 sec)
mysql> select * from user; # 插入之后
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
| 18 | 李白 | 16 |
| 19 | 杜甫 | 42 |
| 20 | 王维 | 29 |
| 21 | 褒姒 | 16 |
| 22 | 貂蝉 | 42 |
| 23 | 飞燕 | 29 |
+----+--------+------+
20 rows in set (0.00 sec)
mysql>
sqlx 高级操作之 IN 查询
查询 ID 在指定集合中的数据
package main
import (
"database/sql/driver"
"fmt"
_ "github.com/go-sql-driver/mysql"
"github.com/jmoiron/sqlx"
)
var db *sqlx.DB
func initDB() (err error) {
dsn := "root:12345678@tcp(127.0.0.1:3306)/sql_test?charset=utf8mb4&parseTime=True"
// 连接到数据库并使用ping进行验证。
// 也可以使用 MustConnect MustConnect连接到数据库，并在出现错误时恐慌 panic。
db, err = sqlx.Connect("mysql", dsn)
if err != nil {
fmt.Printf("connect DB failed, err:%v\n", err)
return
}
db.SetMaxOpenConns(20) // 设置数据库的最大打开连接数。
db.SetMaxIdleConns(10) // 设置空闲连接池中的最大连接数。
return
}
type user struct {
ID int `db:"id"`
Age int `db:"age"`
Name string `db:"name"`
}
// QueryByIDs 查询 ID 在指定集合中的数据
func QueryByIDs(ids []int) (users []user, err error) {
// In 展开args中的切片值，返回修改后的查询字符串和一个可以由数据库执行的新的arg列表。
// “查询”应该使用“?”“bindVar。返回值使用' ?“bindVar
query, args, err := sqlx.In("SELECT name, age FROM user WHERE id IN (?)", ids)
if err != nil {
return nil, err
}
// Rebind 将查询从 QUESTION 转换为DB驱动程序的 bindvar 类型。
query = db.Rebind(query)
// Select 使用此数据库。任何占位符参数都将被提供的参数替换。
err = db.Select(&users, query, args...)
if err != nil {
return nil, err
}
return users, nil
}
func main() {
if err := initDB(); err != nil {
fmt.Printf("init DB failed, err:%v\n", err)
return
}
fmt.Println("init DB succeeded")
// IN 查询
users, err := QueryByIDs([]int{1, 15, 21, 2}) // 默认按照主键顺序排列
if err != nil {
fmt.Printf("query error: %v\n", err)
return
}
fmt.Printf("query successful result users %v\n", users)
for _, user := range users {
fmt.Printf("user: %#v\n", user)
}
}
运行
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜ go run main.go
init DB succeeded
query successful result users [{0 12 小乔} {0 22 小乔} {0 25 刘备} {0 16 褒姒}]
user: main.user{ID:0, Age:12, Name:"小乔"}
user: main.user{ID:0, Age:22, Name:"小乔"}
user: main.user{ID:0, Age:25, Name:"刘备"}
user: main.user{ID:0, Age:16, Name:"褒姒"}
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜
SQL 查询结果
mysql> select * from user;
+----+--------+------+
| id | name | age |
+----+--------+------+
| 1 | 小乔 | 12 |
| 2 | 小乔 | 22 |
| 5 | 昭君 | 18 |
| 6 | 黛玉 | 16 |
| 8 | 李煜 | 26 |
| 9 | Alice | 25 |
| 10 | Bob | 30 |
| 11 | Carol | 28 |
| 12 | Alice1 | 25 |
| 13 | Bob1 | 30 |
| 14 | Carol1 | 28 |
| 15 | 刘备 | 25 |
| 16 | 关羽 | 30 |
| 17 | 张飞 | 28 |
| 18 | 李白 | 16 |
| 19 | 杜甫 | 42 |
| 20 | 王维 | 29 |
| 21 | 褒姒 | 16 |
| 22 | 貂蝉 | 42 |
| 23 | 飞燕 | 29 |
+----+--------+------+
20 rows in set (0.00 sec)
mysql>
-
查询结果默认按照主键顺序排列
-
自定义查询结果顺序
- 使用代码排序
- 使用 MySQL 排序 FIND_IN_SET
sqlx 高级操作之 FIND_IN_SET
package main
import (
"database/sql/driver"
"fmt"
_ "github.com/go-sql-driver/mysql"
"github.com/jmoiron/sqlx"
"strings"
)
var db *sqlx.DB
func initDB() (err error) {
dsn := "root:12345678@tcp(127.0.0.1:3306)/sql_test?charset=utf8mb4&parseTime=True"
// 连接到数据库并使用ping进行验证。
// 也可以使用 MustConnect MustConnect连接到数据库，并在出现错误时恐慌 panic。
db, err = sqlx.Connect("mysql", dsn)
if err != nil {
fmt.Printf("connect DB failed, err:%v\n", err)
return
}
db.SetMaxOpenConns(20) // 设置数据库的最大打开连接数。
db.SetMaxIdleConns(10) // 设置空闲连接池中的最大连接数。
return
}
type user struct {
ID int `db:"id"`
Age int `db:"age"`
Name string `db:"name"`
}
// QueryByIDs 查询 ID 在指定集合中的数据
func QueryByIDs(ids []int) (users []user, err error) {
// In 展开args中的切片值，返回修改后的查询字符串和一个可以由数据库执行的新的arg列表。
// “查询”应该使用“?”“bindVar。返回值使用' ?“bindVar
query, args, err := sqlx.In("SELECT name, age FROM user WHERE id IN (?)", ids)
if err != nil {
return nil, err
}
// Rebind 将查询从 QUESTION 转换为DB驱动程序的 bindvar 类型。
query = db.Rebind(query)
// Select 使用此数据库。任何占位符参数都将被提供的参数替换。
err = db.Select(&users, query, args...)
if err != nil {
return nil, err
}
return users, nil
}
// QueryAndOrderByIDs 根据 ID 在指定集合中和指定顺序查询
func QueryAndOrderByIDs(ids []int) (users []user, err error) {
// 创建一个字符串切片，大小为ids的长度
strIDs := make([]string, 0, len(ids))
// 将ids转换为字符串类型
for _, id := range ids {
// Sprintf根据格式说明符进行格式化，并返回结果字符串。
strIDs = append(strIDs, fmt.Sprintf("%d", id))
}
// In展开args中的切片值，返回修改后的查询字符串和一个可以由数据库执行的新的arg列表。“查询”应该使用“?”“bindVar。返回值使用' ?“bindVar。
query, args, err := sqlx.In("SELECT name, age FROM user WHERE id IN (?) ORDER BY FIND_IN_SET(id, ?)", ids, strings.Join(strIDs, ","))
if err != nil {
return
}
// Rebind 将查询从QUESTION转换为DB驱动程序的bindvar类型。
query = db.Rebind(query)
// 执行查询 Select 使用此数据库。任何占位符参数都将被提供的参数替换。
err = db.Select(&users, query, args...)
return
}
func main() {
if err := initDB(); err != nil {
fmt.Printf("init DB failed, err:%v\n", err)
return
}
fmt.Println("init DB succeeded")
// IN 查询
users, err := QueryByIDs([]int{1, 15, 21, 2})
if err != nil {
fmt.Printf("query error: %v\n", err)
return
}
fmt.Printf("query successful result users %v\n", users)
for _, user := range users {
fmt.Printf("user: %#v\n", user)
}
fmt.Println("**************")
// FIND_IN_SET
users, err = QueryAndOrderByIDs([]int{1, 15, 21, 2})
if err != nil {
fmt.Printf("query error: %v\n", err)
return
}
fmt.Printf("query successful result users %v\n", users)
for _, user := range users {
fmt.Printf("user: %#v\n", user)
}
}
运行
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜ go run main.go
init DB succeeded
query successful result users [{0 12 小乔} {0 22 小乔} {0 25 刘备} {0 16 褒姒}]
user: main.user{ID:0, Age:12, Name:"小乔"}
user: main.user{ID:0, Age:22, Name:"小乔"}
user: main.user{ID:0, Age:25, Name:"刘备"}
user: main.user{ID:0, Age:16, Name:"褒姒"}
**************
query successful result users [{0 12 小乔} {0 25 刘备} {0 16 褒姒} {0 22 小乔}]
user: main.user{ID:0, Age:12, Name:"小乔"} # FIND_IN_SET 按照指定顺序查询
user: main.user{ID:0, Age:25, Name:"刘备"}
user: main.user{ID:0, Age:16, Name:"褒姒"}
user: main.user{ID:0, Age:22, Name:"小乔"}
Code/go/sqlx_demo via 🐹 v1.20.3 via 🅒 base
➜
注意：开发中，使用代码排序还是使用 SQL FIND_IN_SET 查询排序，需要根据开发实际情况来使用。
官方示例
package main
import (
"database/sql"
"fmt"
"log"
_ "github.com/lib/pq"
"github.com/jmoiron/sqlx"
)
var schema = `
CREATE TABLE person (
first_name text,
last_name text,
email text
);
CREATE TABLE place (
country text,
city text NULL,
telcode integer
)`
type Person struct {
FirstName string `db:"first_name"`
LastName string `db:"last_name"`
Email string
}
type Place struct {
Country string
City sql.NullString
TelCode int
}
func main() {
// this Pings the database trying to connect
// use sqlx.Open() for sql.Open() semantics
db, err := sqlx.Connect("postgres", "user=foo dbname=bar sslmode=disable")
if err != nil {
log.Fatalln(err)
}
// exec the schema or fail; multi-statement Exec behavior varies between
// database drivers; pq will exec them all, sqlite3 won't, ymmv
db.MustExec(schema)
tx := db.MustBegin()
tx.MustExec("INSERT INTO person (first_name, last_name, email) VALUES ($1, $2, $3)", "Jason", "Moiron", "jmoiron@jmoiron.net")
tx.MustExec("INSERT INTO person (first_name, last_name, email) VALUES ($1, $2, $3)", "John", "Doe", "johndoeDNE@gmail.net")
tx.MustExec("INSERT INTO place (country, city, telcode) VALUES ($1, $2, $3)", "United States", "New York", "1")
tx.MustExec("INSERT INTO place (country, telcode) VALUES ($1, $2)", "Hong Kong", "852")
tx.MustExec("INSERT INTO place (country, telcode) VALUES ($1, $2)", "Singapore", "65")
// Named queries can use structs, so if you have an existing struct (i.e. person := &Person{}) that you have populated, you can pass it in as &person
tx.NamedExec("INSERT INTO person (first_name, last_name, email) VALUES (:first_name, :last_name, :email)", &Person{"Jane", "Citizen", "jane.citzen@example.com"})
tx.Commit()
// Query the database, storing results in a []Person (wrapped in []interface{})
people := []Person{}
db.Select(&people, "SELECT * FROM person ORDER BY first_name ASC")
jason, john := people[0], people[1]
fmt.Printf("%#v\n%#v", jason, john)
// Person{FirstName:"Jason", LastName:"Moiron", Email:"jmoiron@jmoiron.net"}
// Person{FirstName:"John", LastName:"Doe", Email:"johndoeDNE@gmail.net"}
// You can also get a single result, a la QueryRow
jason = Person{}
err = db.Get(&jason, "SELECT * FROM person WHERE first_name=$1", "Jason")
fmt.Printf("%#v\n", jason)
// Person{FirstName:"Jason", LastName:"Moiron", Email:"jmoiron@jmoiron.net"}
// if you have null fields and use SELECT *, you must use sql.Null* in your struct
places := []Place{}
err = db.Select(&places, "SELECT * FROM place ORDER BY telcode ASC")
if err != nil {
fmt.Println(err)
return
}
usa, singsing, honkers := places[0], places[1], places[2]
fmt.Printf("%#v\n%#v\n%#v\n", usa, singsing, honkers)
// Place{Country:"United States", City:sql.NullString{String:"New York", Valid:true}, TelCode:1}
// Place{Country:"Singapore", City:sql.NullString{String:"", Valid:false}, TelCode:65}
// Place{Country:"Hong Kong", City:sql.NullString{String:"", Valid:false}, TelCode:852}
// Loop through rows using only one struct
place := Place{}
rows, err := db.Queryx("SELECT * FROM place")
for rows.Next() {
err := rows.StructScan(&place)
if err != nil {
log.Fatalln(err)
}
fmt.Printf("%#v\n", place)
}
// Place{Country:"United States", City:sql.NullString{String:"New York", Valid:true}, TelCode:1}
// Place{Country:"Hong Kong", City:sql.NullString{String:"", Valid:false}, TelCode:852}
// Place{Country:"Singapore", City:sql.NullString{String:"", Valid:false}, TelCode:65}
// Named queries, using `:name` as the bindvar. Automatic bindvar support
// which takes into account the dbtype based on the driverName on sqlx.Open/Connect
_, err = db.NamedExec(`INSERT INTO person (first_name,last_name,email) VALUES (:first,:last,:email)`,
map[string]interface{}{
"first": "Bin",
"last": "Smuth",
"email": "bensmith@allblacks.nz",
})
// Selects Mr. Smith from the database
rows, err = db.NamedQuery(`SELECT * FROM person WHERE first_name=:fn`, map[string]interface{}{"fn": "Bin"})
// Named queries can also use structs. Their bind names follow the same rules
// as the name -> db mapping, so struct fields are lowercased and the `db` tag
// is taken into consideration.
rows, err = db.NamedQuery(`SELECT * FROM person WHERE first_name=:first_name`, jason)
// batch insert
// batch insert with structs
personStructs := []Person{
{FirstName: "Ardie", LastName: "Savea", Email: "asavea@ab.co.nz"},
{FirstName: "Sonny Bill", LastName: "Williams", Email: "sbw@ab.co.nz"},
{FirstName: "Ngani", LastName: "Laumape", Email: "nlaumape@ab.co.nz"},
}
_, err = db.NamedExec(`INSERT INTO person (first_name, last_name, email)
VALUES (:first_name, :last_name, :email)`, personStructs)
// batch insert with maps
personMaps := []map[string]interface{}{
{"first_name": "Ardie", "last_name": "Savea", "email": "asavea@ab.co.nz"},
{"first_name": "Sonny Bill", "last_name": "Williams", "email": "sbw@ab.co.nz"},
{"first_name": "Ngani", "last_name": "Laumape", "email": "nlaumape@ab.co.nz"},
}
_, err = db.NamedExec(`INSERT INTO person (first_name, last_name, email)
VALUES (:first_name, :last_name, :email)`, personMaps)
}