创建knex对象

注：页面引用knex.min.js后，才能创建knex
创建不含数据连接的knex对象

var  myknex = new  knex.Client({client: 'mysql',
})

创建含有数据连接的knex对象(待验证)

var  pg = new  knex.Client({client: 'websql',connection: {host : '127.0.0.1',port : 3306,user : 'root',password : '123',database : 'myapp_test'}
})

构建简单的SQL语句

查询语句

简单的单表查询

myknex.queryBuilder().from("table").toQuery()

输出为

select * from "table"

按表字段进行查询①

myknex.queryBuilder().column('title', 'author', 'year').select().from('books').toQuery()

输出为

select "title", "author", "year" from "books"

按表字段进行查询②

myknex.queryBuilder().column(['title', 'author', 'year']).select().from('books').toQuery()

输出为

select "title", "author", "year" from "books"

按表字段进行查询③

myknex.queryBuilder().column('title', {by: 'author'}, 'year').select().from('books').toQuery()

输出为

select "title", "author", "year" from "books"

distinct

myknex.queryBuilder().distinct('first_name', 'last_name').from('users').toQuery()

输出为

select distinct "first_name", "last_name" from "users"

where语句

归纳了where的三种写法

• where(对象)
• where(key,value) //键值对
• where(key,操作符，value)

单条件查询①

myknex.queryBuilder().where('id', 1).from('user').toQuery()

输出为

select * from "user" where "id" = 1

单条件查询②

myknex.queryBuilder().where('votes', '>', 100).from('user').toQuery()

输出为

select * from "users" where "votes" > 100

单条件查询记录集

var subquery =myknex.queryBuilder().where('votes', '>', 100).andWhere('status', 'active').orWhere('name', 'John').select('id').from('users');myknex.queryBuilder().where('id', 'in', subquery).from('users').toQuery()

输出为

select * from "users" where "id" in (select "id" from "users" where "votes" > 100 and "status" = 'active' or "name" = 'John')

where多条件用法①

myknex.queryBuilder().where({first_name: 'zhangsan',last_name:  'lisi'}).select('id').from('user').toQuery()

输出为

select "id" from "user" where "first_name" = 'zhangsan' and "last_name" = 'lisi'

where多条件用法③

myknex.queryBuilder().where(function() {this.where('id', 1).orWhere('id', '>', 10)}).orWhere({name: 'Tester'}).from('users').toQuery()

输出为

select * from "users" where ("id" = 1 or "id" > 10) or ("name" = 'Tester')

where in 用法①

myknex.queryBuilder().where(function (builder) {return builder.whereIn('id', [1, 11, 15]).whereNotIn('id', [17, 19]);}).andWhere(function () {this.where('id', '>', 10);}).from('users').toQuery()

输出为

select * from "users" where ("id" in (1, 11, 15) and "id" not in (17, 19)) and ("id" > 10)

where in 用法②

myknex.queryBuilder().select('name').from('users').whereIn('id', [1, 2, 3]).orWhereIn('id', [4, 5, 6]).toQuery()

输出为

select "name" from "users" where "id" in (1, 2, 3) or "id" in (4, 5, 6)

where in 用法②

myknex.queryBuilder().select('name').from('users').whereIn('account_id', function() {this.select('id').from('accounts');}).toQuery()

输出为

select "name" from "users" where "account_id" in (select "id" from "accounts")

where in 用法④

myknex.queryBuilder().select('name').from('users').whereIn(['account_id', 'email'],       [[3, 'test3@example.com'], [4, 'test4@example.com']]).toQuery()

输出为

select "name" from "users" where ("account_id", "email") in ((3, 'test3@example.com'), (4, 'test4@example.com'))

where in 用法⑤

myknex.queryBuilder().select('name').from('users').whereIn(['account_id', 'email'],myknex.queryBuilder().select('id', 'email').from('accounts')).toQuery()

输出为

select "name" from "users" where ("account_id", "email") in (select "id", "email" from "accounts")

where not in

myknex.queryBuilder().whereNotIn('id', [1, 2, 3]).from('users').toQuery()

输出为

select * from "users" where "id" not in (1, 2, 3)

where or not in

myknex.queryBuilder().where('name', 'like', '%Test%').orWhereNotIn('id', [1, 2, 3]).from('users').toQuery()

输出为

select * from "users" where "name" like '%Test%' or "id" not in (1, 2, 3)

where is null

myknex.queryBuilder().whereNull('updated_at').from('users').toQuery()

输出为

select * from "users" where "updated_at" is null

where is not null

myknex.queryBuilder().whereNotNull('created_at').from('users').toQuery()

输出为

select * from "users" where "created_at" is not null

where like

myknex.queryBuilder().where('columnName', 'like', '%rowlikeme%').from('users').toQuery()

输出为

select * from "users" where "columnName" like '%rowlikeme%'

where exists

myknex.queryBuilder().whereExists(function() {this.select('*').from('accounts').whereRaw('users.account_id = accounts.id');}).toQuery()

输出为

select * where exists (select * from "accounts" where users.account_id = accounts.id)

where not exists

myknex.queryBuilder().whereNotExists(function() {this.select('*').from('accounts').whereRaw('users.account_id = accounts.id');}).toQuery()

输出为

select * where not exists (select * from "accounts" where users.account_id = accounts.id)

where between and

myknex.queryBuilder().whereBetween('votes', [1, 100]).from('users').toQuery()

输出为

select * from "users" where "votes" between 1 and 100

where not between and

myknex.queryBuilder().whereNotBetween('votes', [1, 100]).from('users').toQuery()

输出为

select * from "users" where "votes" not between 1 and 100

where 使用变量

myknex.queryBuilder().whereRaw('id = ?', [1]).from('users').toQuery()

输出为

select * from "users" where id = 1

insert语句

简单inset语句

myknex.queryBuilder().insert({title: 'Slaughterhouse Five'}).into('books').toQuery()

输出为

insert into "books" ("title") values ('Slaughterhouse Five')

含有默认值的inset语句

myknex.queryBuilder().insert([{x: 20}, {y: 30},  {x: 10, y: 20}]).into('books').toQuery()

输出为

insert into "books" ("x", "y") values (20, DEFAULT), (DEFAULT, 30), (10, 20)

update语句

简单update语句

myknex.queryBuilder().from("books").update('title', 'Slaughterhouse Five').where('published_date', '<', 2000).toQuery()

输出为

update "books" set "title" = 'Slaughterhouse Five' where "published_date" < 2000

更新多个字段

myknex.queryBuilder().from("books").update({'title':'Slaughterhouse Five','title1': 'Slaughterhouse Five1'}).where('published_date', '<', 2000).toQuery()

输出为

update "books" set "title" = 'Slaughterhouse Five', "title1" = 'Slaughterhouse Five1' where "published_date" < 2000

delete语句

简单delete语句

myknex.queryBuilder().from("books").where('activated', false).del().toQuery()

输出为

delete from "books" where "activated" = false

表连接

join(table, first, [operator], second)
第一个参数是连接表，接下来的三个参数分别是第一个连接列、连接运算符和第二个连接列,其中连接运算符可以省略

inner join

myknex.queryBuilder().join('contacts', 'users.id', '=', 'contacts.user_id').select('users.id', 'contacts.phone').from('users a').toQuery()

输出为

select "users"."id", "contacts"."phone" from "users a" inner join "contacts" on "users"."id" = "contacts"."user_id"

inner join 存在变量

myknex.queryBuilder().select('*').from('users').join('accounts', 'accounts.type', myknex.raw('?', ['admin'])).toQuery()

输出为

select * from "users" inner join "accounts" on "accounts"."type" = 'admin'

left join

myknex.queryBuilder().select('*').from('users').leftJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" left join "accounts" on "users"."id" = "accounts"."user_id"

left outer join

myknex.queryBuilder().select('*').from('users').leftOuterJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" left outer join "accounts" on "users"."id" = "accounts"."user_id"

right join

myknex.queryBuilder().select('*').from('users').rightJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" right join "accounts" on "users"."id" = "accounts"."user_id"

right outer join

myknex.queryBuilder().select('*').from('users').rightOuterJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" right outer join "accounts" on "users"."id" = "accounts"."user_id"

full outer join

myknex.queryBuilder().select('*').from('users').fullOuterJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" full outer join "accounts" on "users"."id" = "accounts"."user_id"

cross join

只有 MySQL 和 SQLite3 支持交叉连接条件。对于连接条件，请使用innerJoin。

myknex.queryBuilder().select('*').from('users').crossJoin('accounts', 'users.id', 'accounts.user_id').toQuery()

输出为

select * from "users" cross join "accounts" on "users"."id" = "accounts"."user_id"

with语句

with(alias, [columns], callback|builder|raw)
向查询添加“with”子句。PostgreSQL、Oracle、SQLite3 和 MSSQL 支持“With”子句。别名后可以提供可选的列列表；如果提供，它必须至少包含一个列名称

未指定列名称用法

myknex.queryBuilder().with('with_alias', myknex.raw('select * from "books" where "author" = ?', 'Test')).select('*').from('with_alias').toQuery()

输出为

with "with_alias" as (select * from "books" where "author" = 'Test') select * from "with_alias"

制定列名称用法

myknex.queryBuilder().with('with_alias', ["title"], myknex.raw('select "title" from "books" where "author" = ?', 'Test')).select('*').from('with_alias').toQuery()

输出为

with "with_alias"("title") as (select "title" from "books" where "author" = 'Test') select * from "with_alias"

传入callback的用法

myknex.queryBuilder().with('with_alias',function (qb) {qb.select('*').from('books').where('author', 'Test');}).select('*').from('with_alias').toQuery()

输出为

with "with_alias" as (select * from "books" where "author" = 'Test') select * from "with_alias"

with recursive语句

withRecursive(alias, [columns], callback|builder|raw)
与该with方法相同，除了将“递归”附加到“与”（或不附加，根据目标数据库的要求）以使自引用 CTE 成为可能。请注意，某些数据库（例如 Oracle）在使用 rCTE 时需要提供列列表

传入callback的用法

myknex.queryBuilder().with('with_alias',function (qb) {qb.select('*').from('books').where('author', 'Test');}).select('*').from('with_alias').toQuery()

输出为

with "with_alias" as (select * from "books" where "author" = 'Test') select * from "with_alias"

子句

分组 group by

myknex.queryBuilder().groupBy('count').from('users').toQuery()

输出为

select * from "users" group by "count"

排序 order by

单列

不传排序方式时，默认为asc

myknex.queryBuilder().orderBy('email', 'desc').from('users').toQuery()

输出为

select * from "users" order by "email" desc

多列

myknex.queryBuilder().orderBy([{ column: 'email' }, { column: 'age', order: 'desc' }]).from('users').toQuery()

输出为

select * from "users" order by "email" asc, "age" desc

having子句

having

myknex.queryBuilder().groupBy('count').orderBy('name', 'desc').having('count', '>', 100).from('users').toQuery()

输出为

select * from "users" group by "count" having "count" > 100 order by "name" desc

having in

myknex.queryBuilder().havingIn('id', [5, 3, 10, 17]).from('users').toQuery()

输出为

select * from "users" having "id" in (5, 3, 10, 17)

having not in

myknex.queryBuilder().havingNotIn('id', [5, 3, 10, 17]).from('users').toQuery()

输出为

select * from "users" having "id" not in (5, 3, 10, 17)

联合查询

union用法①

myknex.queryBuilder().select('*').from('users').whereNull('last_name').union(function() {this.select('*').from('users').whereNull('first_name')}).toQuery()

输出为

select * from "users" where "last_name" is null union select * from "users" where "first_name" is null

union用法②

myknex.queryBuilder().select('*').from('users').whereNull('last_name').union([myknex.queryBuilder().select('*').from('users').whereNull('first_name')]).toQuery()

输出为

select * from "users" where "last_name" is null union select * from "users" where "first_name" is null

union用法③

myknex.queryBuilder().select('*').from('users').whereNull('last_name').union(myknex.raw('select * from users where first_name is null'),myknex.raw('select * from users where email is null')).toQuery()

输出为

select * from "users" where "last_name" is null union select * from users where first_name is null union select * from users where email is null

unionAll

myknex.queryBuilder().select('*').from('users').whereNull('last_name').unionAll(function() {this.select('*').from('users').whereNull('first_name');}).toQuery()

输出为

select * from "users" where "last_name" is null union all select * from "users" where "first_name" is null

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