（二）sequelize postgres查询

　　findById:根据id查询表数据

　　Executing (default): SELECT "id", "account", "password" FROM "account" AS "account" WHERE "account"."id" = 'test1';

Account.findById('test1', {
    raw: true
}).then(rows => {
    console.log(rows);  //{ id: 'test1', account: '46191', password: '46191' }
}, err => {
    console.log(err);
});

　　findOne:根据条件查询表数据，只取一条

　　Executing (default): SELECT "id", "account", "password" FROM "account" AS "account" WHERE "account"."account" = '46192' LIMIT 1

Account.findOne({
    where: {
        account: '46192'
    },
    raw: true
}).then(rows => {
    console.log(rows); //{ id: 'test2', account: '46192', password: '46192' }
}, err => {
    console.log(err);
});

　　findOrCreate: 查找或创建，若存在符合条件的数据，则返回查询的值和false，不存在则创建数据并返回实例和true，适用单条数据。

　　Executing (2113e55f-3cf9-4e2f-a8e9-84f130a7f103): START TRANSACTION;

　　Executing (2113e55f-3cf9-4e2f-a8e9-84f130a7f103): SELECT "id", "account", "password" FROM "account" AS "account" WHERE "account"."account" = '46192' LIMIT 1;

　　Executing (2113e55f-3cf9-4e2f-a8e9-84f130a7f103): COMMIT;

Account.findOrCreate({
    where: {
        account: '46192'
    },
    defaults:{id: 'test5'},
    raw: true
}).then(rows => {      //将then改为spread，返回值rows是(rows[0], rows[1])
    console.log(rows); //[ { id: 'test2', account: '46192', password: '46192' }, false ]
}, err => {
    console.log(err);
});

　　Executing (a6e8ce63-56c0-4d36-beb3-467ccde1b6e9): START TRANSACTION;　　

　　Executing (a6e8ce63-56c0-4d36-beb3-467ccde1b6e9): SELECT "id", "account", "password" FROM "account" AS "account" WHERE "account"."account" = '46195' LIMIT 1;

　　Executing (a6e8ce63-56c0-4d36-beb3-467ccde1b6e9): CREATE OR REPLACE FUNCTION pg_temp.testfunc(OUT response "account", OUT sequelize_caught_exception text) RETURNS RECORD AS $func_c0fa0d6a908548f6a82c0b0de9611536$ BEGIN INSERT INTO "account" ("id","account") VALUES ('test5','46195') RETURNING * INTO response; EXCEPTION WHEN unique_violation THEN GET STACKED DIAGNOSTICS sequelize_caught_exception = PG_EXCEPTION_DETAIL; END $func_c0fa0d6a908548f6a82c0b0de9611536$ LANGUAGE plpgsql; SELECT (testfunc.response).*, testfunc.sequelize_caught_exception FROM pg_temp.testfunc(); DROP FUNCTION IF EXISTS pg_temp.testfunc();

　　Executing (a6e8ce63-56c0-4d36-beb3-467ccde1b6e9): COMMIT;

Account.findOrCreate({
    where: {
        account: '46195'
    },
    defaults:{id: 'test5'},
    raw: true
}).then(rows => {
    console.log(rows); //[ account实例, true]
}, err => {
    console.log(err);
});

　　findAndCount:查找并统计数量

　　Executing (default): SELECT "id", "account", "password" FROM "account" AS "account" WHERE "account"."id" IN ('test1', 'test2');

Account.findAndCount({
    where: {
        id: ['test1', 'test2']
    },
    raw: true
}).then(res => {
    console.log(res); //{count: 2, rows:[{id: 'test1', account: '46191', password: '46191'},{id: 'test2', account: '46192', password: '46192'}]}
}, err => {
    console.log(err);
});

　　findAll:查找所有符合条件的数据

　　count:计算符合条件数据的总数，返回值是整数

　　max，min根据列名取最大最小值，若取不到返回null

Account.max('id').then(max => {
    console.log(max); //test7
}, err => {
    console.log(err);
});

　　各种条件，where中能够实现and,or,>,<,in等

Account.findAll({
    attributes: [],     //属性
    where: {            //条件
        id: '',
        account: ''
    },
    group: '',           //分组
    order: '',           //排序，可为数组
    limit: 0,            //查询条数，相当于sql的top
    offset: 0            //跳过多少条
}).then(rows => {
    console.log(rows); 
}, err => {
    console.log(err);
});

Sequelize Model usage