import { DeleteResult, InsertOption, InsertResult, SelectOption, UpdateOption, UpdateResult, UpdateRow } from "../types";
import { Operator } from "./operator";
import { Transaction } from "./transaction";
import { Pool } from "mysql2";
import { QueryResult } from 'mysql2/typings/mysql/lib/protocol/packets';
export declare class Client extends Operator {
    private pool;
    constructor(pool: Pool);
    getTransaction(): Promise<Transaction>;
    query<T extends QueryResult>(sql: string, params?: any[] | object): Promise<T>;
    queryOne<T extends QueryResult>(sql: string, params?: any[] | object): Promise<T | undefined>;
    count(table: string, where?: object): Promise<number>;
    /**
     * Select rows from a table
     *
     * @param  {String} table     table name
     * @param  {Object} [option] optional params
     *  - {Object} where          query condition object
     *  - {Array|String} columns  select columns, default is `'*'`
     *  - {Array|String} orders   result rows sort condition
     *  - {Number} limit          result limit count, default is no limit
     *  - {Number} offset         result offset, default is `0`
     * @return {Array} result rows
     */
    select<T = any>(table: string, option?: SelectOption): Promise<T[]>;
    get<T = any>(table: string, where?: object, option?: SelectOption): Promise<T>;
    insert(table: string, rows: object | object[], option?: InsertOption): Promise<InsertResult>;
    update(table: string, row: object, option?: UpdateOption): Promise<UpdateResult>;
    /**
     * Update multiple rows from a table
     *
     * UPDATE `table_name` SET
     *  `column1` CASE
     *     WHEN  condition1 THEN 'value11'
     *     WHEN  condition2 THEN 'value12'
     *     WHEN  condition3 THEN 'value13'
     *     ELSE `column1` END,
     *  `column2` CASE
     *     WHEN  condition1 THEN 'value21'
     *     WHEN  condition2 THEN 'value22'
     *     WHEN  condition3 THEN 'value23'
     *     ELSE `column2` END
     * WHERE condition
     *
     * See MySQL Case Syntax: https://dev.mysql.com/doc/refman/5.7/en/case.html
     *
     * @param {String} table table name
     * @param {Array<Object>} updateRows Object Arrays
     *    each Object needs a primary key `id`, or each Object has `row` and `where` properties
     *    e.g.
     *      [{ id: 1, name: 'fengmk21' }]
     *      or [{ row: { name: 'fengmk21' }, where: { id: 1 } }]
     * @return {object} update result
     */
    updateRows(table: string, updateRows: UpdateRow[]): Promise<UpdateResult>;
    delete(table: string, where?: object | null): Promise<DeleteResult>;
}