node.js - 如何在 knex 中使用嵌套选择查询

Question

我想使用 knex 添加子查询作为列。
SQL 查询示例:

select
    name, 
    (select count(*) from employee where employee.dept_id = 1) as employees_count
 from 
    department
 where
    department.id = 1

我尝试过

knex('department').select('name', knex('employee').count().where({dept_id: 1}))
.where({id: 1})

但没有成功

Answer 1

const Knex = require('knex');


const knex = Knex({
  client: 'pg',
});

knex('department').select(
  'name', 
  knex('employee').count().where({dept_id: 1})
    .as('employees_count')
).where({id: 1}).toSQL().sql;

// "select \"name\", (select count(*) from \"employee\" where… \"employees_count\" from \"department\" where \"id\" = ?"

https://runkit.com/embed/q22w8v6z5n61