使用mysql2@1.7.0、类型脚本@3.6.3、@类型/mysql2
接口必须扩展RowDataPacket：

interface IUser extends RowDataPacket {
  ssid: string
}

从那里你可以传入类型：

const [rows]: [IUser[], FieldPacket[]] = await connection.query<IUser[]>("SELECT ssid FROM user", [])

或者干脆

const [rows] = await connection.query<IUser[]>("SELECT ssid FROM user", [])

// the function should return a Promise that resolves to 
{ uid: number, uname: string }

// but typeof rows is 
{ rows: { uid: number, uname: string } }

执行该示例，得到的结果如下所示：

[ TextRow { uid: 1, uname: 'foo', email: 'foo@mail.com' } ]

因此，pool.query 返回一个数组，其中IUser数组作为第一个元素。
返回多个用户：

class UserController {
    // returns all users
    public async getUsers(): Promise<Array<IUser>> {
        const [rows]: [Array<IUser>] = await pool.query(
                "SELECT * FROM `user`", []);
        return rows; // rows is Array<IUser> so it matches the promise type
    }
}

返回特定用户：

class UserController {
    public async getUser(id: number): Promise<IUser> { // Note the 
        const [rows]: [Array<IUser>] = 
            await pool.query("SELECT * FROM `user` WHERE `email` = ?",
                            ["foo@mail.com"]);
        // If email is unique as it would be expected it will 
        // return a single value inside an array
        // rows is still Array<IUser>
        return rows[0]; // rows[0] is an IUser 
    }
}

当我试图设置稍后要使用的变量时，使用pool.query<type>对我来说是不够的，因为数据类型RowDataPacket仍然侵犯了我的类型...
我最终为pool的query函数创建了一个 Package 器，如下所示：

type Row = import("mysql2").RowDataPacket
type Ok = import("mysql2").OkPacket
type dbDefaults = Row[] | Row[][] | Ok[] | Ok
type dbQuery<T> = T & dbDefaults

export const db = {
  query: async <T>(query: string, params?: Array<any>): Promise<[T, any]> => {
    return pool.promise().query<dbQuery<T>>(query, params)
  },
}

这允许我在项目的其他部分使用query函数，类似于其他答案，如

let result = await db.query<desiredType>("SELECT", [optionalArgs])

但是它去掉了RowDataPacket的类型信息等等。

我有同样的错误，所以我在谷歌搜索，发现这个例子：https://github.com/types/mysql2/blob/master/test/promise.ts
我代码是这样的

const [user] = await pool.query<RowDataPacket[]>("SELECT * FROM Users WHERE email = ?", [email]);
        if(!user.length) {
            throw {
                error: true,
                message: 'no user founded'
            } 
        }

有了这个，我就可以使用vs代码的自动完成功能，而且不会出现错误

我觉得这个很好用

import {RowDataPacket} from 'mysql2'

      const [rows]= await pool.query<IUser[] & RowDataPacket[][]>(
          "SELECT * FROM `users` LIMIT 3");

接受答案中的方法对我不起作用（typescript@3.5.2，mysql2@1.6.5）。

interface IUserRow {
  ssid: string
}

const [rows]: [IUserRow[]] = await pool.query(
  'select ssid from user where id = ?',
  [session.userId],
)

给了我

error TS2322: Type '[RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[], FieldPacket[]]' is not assignable to type '[IUserRow[]]'.
  Types of property '0' are incompatible.
    Type 'RowDataPacket[] | RowDataPacket[][] | OkPacket | OkPacket[]' is not assignable to type 'IUserRow[]'.
      Type 'RowDataPacket[]' is not assignable to type 'IUserRow[]'.
        Property 'ssid' is missing in type 'RowDataPacket' but required in type 'IUserRow'.

突出显示[rows]。
我能够让一切工作与：

interface IUserRow {
  ssid: string
}

const [rows] = await pool.query(
  'select ssid from user where id = ?',
  [session.userId],
)

// This first if statement is a type guard against rows possibly being OkPacket
if (Array.isArray(rows) && rows.length > 0) {
  // The casting works fine here
  const userRow = rows[0] as IUserRow
  if (userRow.ssid !== session.ssid) {
    ...
  }
}

我不是打字Maven，所以可能有更好的方法来做到这一点!尽管如此，我希望我可以潜在地节省一些人的挫折，如果他们也有问题的接受答案。