golang mysql 条件查询 golang sql server

在 Ubuntu 使用SQL Server创建 Go 应用程序

• 一、设置环境

• 1.1、安装 SQL Server
• 1.2、安装 GoLang
• 1.3、安装 ODBC 驱动程序和 SQL 命令行实用工具 SQL 服务器

• 二、使用 SQL 服务器创建 Go 应用程序

• 2.1、创建连接到 SQL Server 并执行查询的 Go 应用
• 2.2、创建一个使用 GORM 连接到 SQL Server 的 Go 应用程序

• 三、让 Go 应用的速度提高 100 倍

• 3.1、使用 sqlcmd 创建一个包含 5 万个的新表
• 3.2、创建一个 Go 应用程序，用于查询此表并测量所花费的时间
• 3.3、测量运行查询所需的时间
• 3.4、使用 SQLCMD 向表中添加列存储索引
• 3.5、重新运行 columnstore.go 脚本，并注意这次完成查询所花费的时间

• 总结

一、设置环境

在 Ubuntu 机器上安装 SQL Server 2017和安装运行 GoLang 所需的依赖项。

1.1、安装 SQL Server

为了确保 SQL Server 的最佳性能，计算机应至少具有 4 GB 的内存。

（1）注册 Microsoft Linux 存储库并添加其密钥。

curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -
curl https://packages.microsoft.com/config/ubuntu/16.04/mssql-server-2017.list | sudo tee /etc/apt/sources.list.d/mssql-server-2017.list

（2）安装 SQL Server。

sudo apt-get update
sudo apt-get install mssql-server

执行结果：

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
  mssql-server
...
Unpacking mssql-server ...
Setting up mssql-server ...

（3）设置 SQL Server。

sudo /opt/mssql/bin/mssql-conf setup

执行结果：

Microsoft(R) SQL Server(R) Setup

To abort setup at anytime, press Ctrl-C.

The license terms for this product can be downloaded from http://go.microsoft.com/fwlink/?LinkId=746388 and
found in /usr/share/doc/mssql-server/LICENSE.TXT.

Do you accept the license terms? If so, please type YES:
Please enter a password for the system administrator (SA) account:
Please confirm the password for the system administrator (SA) account:

1.2、安装 GoLang

如果您的机器上已经安装了 Go，请跳过此步骤。

（1）下载安装。

curl -O https://storage.googleapis.com/golang/go1.8.linux-amd64.tar.gz
tar xvf go1.8.linux-amd64.tar.gz
sudo chown -R root:root ./go
sudo mv go /usr/local

（2）将这两行添加到 ~/.profile 文件中。

export GOPATH=$HOME/work
export PATH=$PATH:/usr/local/go/bin:$GOPATH/bin

1.3、安装 ODBC 驱动程序和 SQL 命令行实用工具 SQL 服务器

SQLCMD 是一个命令行工具，能够连接到 SQL Server 并运行查询。

（1）下载适用于操作系统版本的软件包。

sudo su
curl https://packages.microsoft.com/keys/microsoft.asc | apt-key add -

#Download appropriate package for the OS version
#Choose only ONE of the following, corresponding to your OS version

#Ubuntu 16.04
curl https://packages.microsoft.com/config/ubuntu/16.04/prod.list > /etc/apt/sources.list.d/mssql-release.list

#Ubuntu 18.04
curl https://packages.microsoft.com/config/ubuntu/18.04/prod.list > /etc/apt/sources.list.d/mssql-release.list

#Ubuntu 19.10
curl https://packages.microsoft.com/config/ubuntu/19.10/prod.list > /etc/apt/sources.list.d/mssql-release.list

exit
sudo apt-get update
sudo ACCEPT_EULA=Y apt-get install msodbcsql17
# optional: for bcp and sqlcmd
sudo ACCEPT_EULA=Y apt-get install mssql-tools
echo 'export PATH="$PATH:/opt/mssql-tools/bin"' >> ~/.bash_profile
echo 'export PATH="$PATH:/opt/mssql-tools/bin"' >> ~/.bashrc
source ~/.bashrc
# optional: for unixODBC development headers
sudo apt-get install unixodbc-dev

（2）安装 SQLCMD 后，可以使用以下命令连接到 SQL Server：

sqlcmd -S localhost -U sa -P yourpassword
1> # You're connected! Type your T-SQL statements here. Use the keyword 'GO' to execute each batch of statements.

（3）测试数据库。结果将打印到标准输出。

sqlcmd -S localhost -U sa -P yourpassword -Q "SELECT @@VERSION"

--------------------------------------------------------
Microsoft SQL Server vNext (CTP2.0) - 14.0.500.272 (X64)
	Apr 2 2023 11:44:40
	Copyright (c) Microsoft Corporation
    on Linux (Ubuntu 16.04)

1 rows(s) returned

Executed in 1 ns

至此，已成功在 Ubuntu 机器上安装 SQL Server 命令行实用程序，已经在 Ubuntu 计算机上成功安装并设置 GoLang 和 mssql-tools。现在拥有开始使用 SQL Server 编写 Go 应用程序所需的一切。

二、使用 SQL 服务器创建 Go 应用程序

安装 SQL Server 和 GoLang 后，现在可以继续创建新的 Go 项目。在这里，将探讨三个简单的应用程序。其中一个将连接并打印数据库服务器的SQL Server版本，另一个将执行基本的插入，更新，删除和选择操作，第三个将使用GORM，一种流行的对象关系映射（ORM）框架，用于Go执行相同的操作。

2.1、创建连接到 SQL Server 并执行查询的 Go 应用

（1）创建新的项目目录并安装 Go 依赖项。

cd ~/

#Create Project Directory
mkdir SqlServerSample
cd SqlServerSample

# Get and install the SQL Server driver for Go
go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb

（2）通过使用 sqlcmd 连接到 SQL Server 并执行以下命令，创建将用于本教程其余部分的数据库。不要忘记使用自己的用户名和密码更新用户名和密码。

sqlcmd -S 127.0.0.1 -U sa -P <你的> -Q "CREATE DATABASE SampleDB;"

（3）创建一个连接到 SQL Server 的简单 Go 应用。
在 SqlServerSample 文件夹中创建一个名为 connect.go 的文件。将以下内容复制并粘贴到文件中。不要忘记使用自己的用户名和密码更新用户名和密码。
此示例使用 GoLang 上下文方法来确保存在与数据库服务器的活动连接。

package main

import (
    _ "github.com/denisenkom/go-mssqldb"
    "database/sql"
    "context"
    "log"
    "fmt"
)

// Replace with your own connection parameters
var server = "localhost"
var port = 1433
var user = "sa"
var password = "xxxxxx"

var db *sql.DB

func main() {
    var err error

    // Create connection string
    connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d",
        server, user, password, port)

    // Create connection pool
    db, err = sql.Open("sqlserver", connString)
    if err != nil {
        log.Fatal("Error creating connection pool: " + err.Error())
    }
    log.Printf("Connected!\n")

    // Close the database connection pool after program executes
    defer db.Close()

    SelectVersion()
}

// Gets and prints SQL Server version
func SelectVersion(){
    // Use background context
    ctx := context.Background()

    // Ping database to see if it's still alive.
    // Important for handling network issues and long queries.
    err := db.PingContext(ctx)
    if err != nil {
        log.Fatal("Error pinging database: " + err.Error())
    }

    var result string

    // Run query and scan for result
    err = db.QueryRowContext(ctx, "SELECT @@version").Scan(&result)
    if err != nil {
        log.Fatal("Scan failed:", err.Error())
    }
    fmt.Printf("%s\n", result)
}

（4）运行应用程序。

go run connect.go

执行结果：

Connected!
Microsoft SQL Server 2017 (CTP2.1) - 14.0.600.250 (X64)
        Apr 2 2017 12:21:23
        Copyright (C) 2017 Microsoft Corporation. All rights reserved.
        Developer Edition (64-bit) on Linux (Ubuntu 16.04.2 LTS)

（5）在 SqlServerSample 文件夹中创建一个名为 CreateTestData 的文件.sql。将以下 T-SQL 代码复制并粘贴到其中。这将创建一个架构、表并插入几行。

CREATE SCHEMA TestSchema;
GO

CREATE TABLE TestSchema.Employees (
  Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
  Name NVARCHAR(50),
  Location NVARCHAR(50)
);
GO

INSERT INTO TestSchema.Employees (Name, Location) VALUES
(N'Jared', N'Australia'),
(N'Nikita', N'India'),
(N'Tom', N'Germany');
GO

SELECT * FROM TestSchema.Employees;
GO

（6）使用 sqlcmd 连接到数据库并运行 SQL 脚本以创建架构、表并插入一些行。

sqlcmd -S 127.0.0.1 -U sa -P <你的> -d SampleDB -i ./CreateTestData.sql

执行结果：

CREATE SCHEMA TestSchema;

Executed in 0 ms
CREATE TABLE TestSchema.Employees (
  Id INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
  Name NVARCHAR(50),
  Location NVARCHAR(50)
);

Executed in 0 ms
INSERT INTO TestSchema.Employees (Name, Location) VALUES
(N'Jared', N'Australia'),
(N'Nikita', N'India'),
(N'Tom', N'Germany');

Executed in 0 ms
SELECT * FROM TestSchema.Employees;
Id  Name    Location
--  ------  ---------
1   Jared   Australia
2   Nikita  India
3   Tom     Germany

3 row(s) returned

Executed in 1 ms

（7）在 SqlServerSample 文件夹中创建一个名为 crud.go 的新文件。将以下代码复制并粘贴到其中。这将插入、更新、删除和读取几行。

package main

import (
    _ "github.com/denisenkom/go-mssqldb"
    "database/sql"
    "context"
    "log"
    "fmt"
    "errors"
)

var db *sql.DB

var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"

func main() {
    // Build connection string
    connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s;",
        server, user, password, port, database)

    var err error

    // Create connection pool
    db, err = sql.Open("sqlserver", connString)
    if err != nil {
        log.Fatal("Error creating connection pool: ", err.Error())
    }
    ctx := context.Background()
    err = db.PingContext(ctx)
    if err != nil {
        log.Fatal(err.Error())
    }
    fmt.Printf("Connected!\n")

    // Create employee
    createID, err := CreateEmployee("Jake", "United States")
    if err != nil {
        log.Fatal("Error creating Employee: ", err.Error())
    }
    fmt.Printf("Inserted ID: %d successfully.\n", createID)

    // Read employees
    count, err := ReadEmployees()
    if err != nil {
        log.Fatal("Error reading Employees: ", err.Error())
    }
    fmt.Printf("Read %d row(s) successfully.\n", count)

    // Update from database
    updatedRows, err := UpdateEmployee("Jake", "Poland")
    if err != nil {
        log.Fatal("Error updating Employee: ", err.Error())
    }
    fmt.Printf("Updated %d row(s) successfully.\n", updatedRows)

    // Delete from database
    deletedRows, err := DeleteEmployee("Jake")
    if err != nil {
        log.Fatal("Error deleting Employee: ", err.Error())
    }
    fmt.Printf("Deleted %d row(s) successfully.\n", deletedRows)
}

// CreateEmployee inserts an employee record
func CreateEmployee(name string, location string) (int64, error) {
    ctx := context.Background()
    var err error

    if db == nil {
        err = errors.New("CreateEmployee: db is null")
        return -1, err
    }

    // Check if database is alive.
    err = db.PingContext(ctx)
    if err != nil {
        return -1, err
    }

    tsql := "INSERT INTO TestSchema.Employees (Name, Location) VALUES (@Name, @Location); select convert(bigint, SCOPE_IDENTITY());"

    stmt, err := db.Prepare(tsql)
    if err != nil {
        return -1, err
    }
    defer stmt.Close()

    row := stmt.QueryRowContext(
        ctx,
        sql.Named("Name", name),
        sql.Named("Location", location))
    var newID int64
    err = row.Scan(&newID)
    if err != nil {
        return -1, err
    }

    return newID, nil
}

// ReadEmployees reads all employee records
func ReadEmployees() (int, error) {
    ctx := context.Background()

    // Check if database is alive.
    err := db.PingContext(ctx)
    if err != nil {
        return -1, err
    }

    tsql := fmt.Sprintf("SELECT Id, Name, Location FROM TestSchema.Employees;")

    // Execute query
    rows, err := db.QueryContext(ctx, tsql)
    if err != nil {
        return -1, err
    }

    defer rows.Close()

    var count int

    // Iterate through the result set.
    for rows.Next() {
        var name, location string
        var id int

        // Get values from row.
        err := rows.Scan(&id, &name, &location)
        if err != nil {
            return -1, err
        }

        fmt.Printf("ID: %d, Name: %s, Location: %s\n", id, name, location)
        count++
    }

    return count, nil
}

// UpdateEmployee updates an employee's information
func UpdateEmployee(name string, location string) (int64, error) {
    ctx := context.Background()

    // Check if database is alive.
    err := db.PingContext(ctx)
    if err != nil {
        return -1, err
    }

    tsql := fmt.Sprintf("UPDATE TestSchema.Employees SET Location = @Location WHERE Name = @Name")

    // Execute non-query with named parameters
    result, err := db.ExecContext(
        ctx,
        tsql,
        sql.Named("Location", location),
        sql.Named("Name", name))
    if err != nil {
        return -1, err
    }

    return result.RowsAffected()
}

// DeleteEmployee deletes an employee from the database
func DeleteEmployee(name string) (int64, error) {
    ctx := context.Background()

    // Check if database is alive.
    err := db.PingContext(ctx)
    if err != nil {
        return -1, err
    }

    tsql := fmt.Sprintf("DELETE FROM TestSchema.Employees WHERE Name = @Name;")

    // Execute non-query with named parameters
    result, err := db.ExecContext(ctx, tsql, sql.Named("Name", name))
    if err != nil {
        return -1, err
    }

    return result.RowsAffected()
}

（8）运行 crud.go 应用以查看结果。

go run crud.go

执行结果：

Connected!
Inserted ID: 4 successfully.
ID: 1, Name: Jared, Location: Australia
ID: 2, Name: Nikita, Location: India
ID: 3, Name: Tom, Location: Germany
ID: 4, Name: Jake, Location: United States
Read 4 row(s) successfully.
Updated 1 row(s) successfully.
Deleted 1 row(s) successfully.

2.2、创建一个使用 GORM 连接到 SQL Server 的 Go 应用程序

（1）创建应用目录并初始化 Go 依赖项。

cd ~/
mkdir SqlServerGormSample
cd SqlServerGormSample

# Get and install the SQL Server driver for Go
go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb

（2）将以下内容粘贴到名为orm.go的文件中。确保将密码变量替换为您自己的变量。

package main

import (
    "fmt"
    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mssql"
    "log"
)

var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"

// Define a User model struct
type User struct {
    gorm.Model
    FirstName string
    LastName string
}

// Define a Task model struct
type Task struct {
    gorm.Model
    Title string
    DueDate string
    IsComplete bool
    UserID  uint
}

// Read and print all the tasks
func ReadAllTasks(db *gorm.DB){
    var users []User
    var tasks []Task
    db.Find(&users)

    for _, user := range users{
        db.Model(&user).Related(&tasks)
        fmt.Printf("%s %s's tasks:\n", user.FirstName, user.LastName)
        for _, task := range tasks {
            fmt.Printf("Title: %s\nDueDate: %s\nIsComplete:%t\n\n",
                            task.Title, task.DueDate, task.IsComplete)
        }
    }
}

// Update a task based on a user
func UpdateSomeonesTask(db *gorm.DB, userId int){
    var task Task
    db.Where("user_id = ?", userId).First(&task).Update("Title", "Buy donuts for Luis")
    fmt.Printf("Title: %s\nDueDate: %s\nIsComplete:%t\n\n",
                    task.Title, task.DueDate, task.IsComplete)
}

// Delete all the tasks for a user
func DeleteSomeonesTasks(db *gorm.DB, userId int){
    db.Where("user_id = ?", userId).Delete(&Task{})
    fmt.Printf("Deleted all tasks for user %d", userId)
}

func main() {
    connectionString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s",
                                        server, user, password, port, database)
    db, err := gorm.Open("mssql", connectionString)

    if err != nil {
        log.Fatal("Failed to create connection pool. Error: " + err.Error())
    }
    gorm.DefaultCallback.Create().Remove("mssql:set_identity_insert")
    defer db.Close()

    fmt.Println("Migrating models...")
    db.AutoMigrate(&User{})
    db.AutoMigrate(&Task{})

    // Create awesome Users
    fmt.Println("Creating awesome users...")
    db.Create(&User{FirstName: "Andrea", LastName: "Lam"})      //UserID: 1
    db.Create(&User{FirstName: "Meet", LastName: "Bhagdev"})    //UserID: 2
    db.Create(&User{FirstName: "Luis", LastName: "Bosquez"})    //UserID: 3

    // Create appropriate Tasks for each user
    fmt.Println("Creating new appropriate tasks...")
    db.Create(&Task{
        Title: "Do laundry", DueDate: "2017-03-30", IsComplete: false, UserID: 1})
    db.Create(&Task{
        Title: "Mow the lawn", DueDate: "2017-03-30", IsComplete: false, UserID: 2})
    db.Create(&Task{
        Title: "Do more laundry", DueDate: "2017-03-30", IsComplete: false, UserID: 3})
    db.Create(&Task{
        Title: "Watch TV", DueDate: "2017-03-30", IsComplete: false, UserID: 3})

    // Read
    fmt.Println("\nReading all the tasks...")
    ReadAllTasks(db)

    // Update - update Task title to something more appropriate
    fmt.Println("Updating Andrea's task...")
    UpdateSomeonesTask(db, 1)

    // Delete - delete Luis's task
    DeleteSomeonesTasks(db, 3)
}

（3）运行 orm.go 应用。

go run orm.go

执行结果：

[info] removing callback `mssql:set_identity_insert` from C:/Projects/golang-experiments/tutorials/orm.go:70
Migrating models...
Creating awesome users...
Creating new appropriate tasks...

Reading all the tasks...
Andrea Lam's tasks:
Title: Do laundry
DueDate: 2017-03-30
IsComplete:false

Meet Bhagdev's tasks:
Title: Mow the lawn
DueDate: 2017-03-30
IsComplete:false

Luis Bosquez's tasks:
Title: Do more laundry
DueDate: 2017-03-30
IsComplete:false

Title: Watch TV
DueDate: 2017-03-30
IsComplete:false

Updating Andrea's task...
Title: Buy donuts for Luis
DueDate: 2017-03-30
IsComplete:false

Deleted all tasks for user 3

三、让 Go 应用的速度提高 100 倍

已了解基础知识，接下来可以了解如何使用 SQL Server 改进应用。通过列存储索引的简单示例，以及它们如何提高数据处理速度。与传统行存储索引相比，列存储索引在分析工作负荷上可实现高达 100 倍的性能，并将数据压缩提高多达 10 倍。

3.1、使用 sqlcmd 创建一个包含 5 万个的新表

（1）切换到主目录并为项目创建一个文件夹。

cd ~/
mkdir SqlServerColumnstoreSample
cd SqlServerColumnstoreSample

（2）在 SqlServerColumnstoreSample 文件夹中创建一个名为 CreateSampleTable 的新文件.sql文件。将下面的 T-SQL 代码粘贴到新的 SQL 文件中。保存并关闭文件。

WITH a AS (SELECT * FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),(10)) AS a(a))
SELECT TOP(5000000)
ROW_NUMBER() OVER (ORDER BY a.a) AS OrderItemId
,a.a + b.a + c.a + d.a + e.a + f.a + g.a + h.a AS OrderId
,a.a * 10 AS Price
,CONCAT(a.a, N' ', b.a, N' ', c.a, N' ', d.a, N' ', e.a, N' ', f.a, N' ', g.a, N' ', h.a) AS ProductName
INTO Table_with_5M_rows
FROM a, a AS b, a AS c, a AS d, a AS e, a AS f, a AS g, a AS h;

（3）使用 sqlcmd 连接到数据库并运行 SQL 脚本以创建包含 5 万行的表。这可能需要几分钟才能运行。

sqlcmd -S 127.0.0.1 -U sa -P <你的> -d SampleDB -i ./CreateSampleTable.sql

3.2、创建一个 Go 应用程序，用于查询此表并测量所花费的时间

（1）在项目文件夹中，初始化 Go 依赖项。

go get github.com/denisenkom/go-mssqldb
go install github.com/denisenkom/go-mssqldb

（2）在您的文件夹中创建一个名为 columnstore.go 的文件。

package main

import (
    _ "github.com/denisenkom/go-mssqldb"
    "database/sql"
    "context"
    "log"
    "fmt"
    "time"
)

var server = "localhost"
var port = 1433
var user = "sa"
var password = "你的"
var database = "SampleDB"

var db *sql.DB

// Delete an employee from database
func ExecuteAggregateStatement(db *sql.DB) {
    ctx := context.Background()

    // Ping database to see if it's still alive.
    // Important for handling network issues and long queries.
    err := db.PingContext(ctx)
    if err != nil {
        log.Fatal("Error pinging database: " + err.Error())
    }

    var result string

    // Execute long non-query to aggregate rows
    err = db.QueryRowContext(ctx, "SELECT SUM(Price) as sum FROM Table_with_5M_rows").Scan(&result)
    if err != nil {
        log.Fatal("Error executing query: " + err.Error())
    }

    fmt.Printf("Sum: %s\n", result)
}

func main() {
    // Connect to database
    connString := fmt.Sprintf("server=%s;user id=%s;password=%s;port=%d;database=%s;",
                                server, user, password, port, database)
    var err error

    // Create connection pool
    db, err = sql.Open("sqlserver", connString)
    if err != nil {
        log.Fatal("Open connection failed:", err.Error())
    }
    fmt.Printf("Connected!\n")

    defer db.Close()

    t1 := time.Now()
    fmt.Printf("Start time: %s\n", t1)

    ExecuteAggregateStatement(db)

    t2 := time.Since(t1)
    fmt.Printf("The query took: %s\n", t2)
}

3.3、测量运行查询所需的时间

从终端运行 Go 应用。

go run columnstore.go

执行结果：

Connected!
Start time: 2023-04-02 15:33:50.0340976 -0700 PDT
Sum: 50000000
The query took: 601.7463ms

3.4、使用 SQLCMD 向表中添加列存储索引

运行以下命令以在表上创建列存储索引：

sqlcmd -S localhost -U sa -P <你的> -d SampleDB -Q "CREATE CLUSTERED COLUMNSTORE INDEX Columnstoreindex ON Table_with_5M_rows;"

3.5、重新运行 columnstore.go 脚本，并注意这次完成查询所花费的时间

go run columnstore.go

Connected!
Start time: 2017-06-05 16:35:02.5409285 -0700 PDT
Sum: 50000000
The query took: 86.9826ms

总结

1. 使用列存储索引使 Go 应用更快。
2. 参考文档。