集合运算

SQL 集合运算将多个查询块的结果合并为一个单一结果。
SQL 标准定义了以下三种集合运算：UNION、INTERSECT、EXCEPT、UNION ALL、INTERSECT ALL、EXCEPT ALL。

并集

将两个查询块的所有结果合并为一个结果，并省略任何重复项。

从 customers 和 users 表中获取所有不重复的名称。

import-pattern

builder-pattern

schema.ts

import { union } from 'drizzle-orm/pg-core'
import { users, customers } from './schema'

const allNamesForUserQuery = db.select({ name: users.name }).from(users);

const result = await union(
	allNamesForUserQuery,
	db.select({ name: customers.name }).from(customers)
).limit(10);

(select "name" from "sellers")
union
(select "name" from "customers")
limit $1 -- 参数: [10]

import { users, customers } from './schema'

const result = await db
  .select({ name: users.name })
  .from(users)
  .union(db.select({ name: customers.name }).from(customers))
  .limit(10);

(select "name" from "sellers")
union
(select "name" from "customers")
limit $1 -- 参数: [10]

import { integer, pgTable, text, varchar } from "drizzle-orm/pg-core";

export const users = pgTable('sellers', {
    id: integer().primaryKey(),
    name: varchar({ length: 256 }).notNull(),
    address: text(),
});

export const customers = pgTable('customers', {
    id: integer().primaryKey(),
    name: varchar({ length: 256 }).notNull(),
    city: text(),
    email: varchar({ length: 256 }).notNull()
});

Union All

将两个查询块中的所有结果合并为一个结果，保留重复项。

让我们考虑一个场景：你有两张表，一张表示在线销售，另一张表示门店销售。在这种情况下，你希望将这两张表中的数据合并为一个结果集。由于可能存在重复交易，你希望保留所有记录，而不消除重复项。

import-pattern

builder-pattern

schema.ts

import { unionAll } from 'drizzle-orm/pg-core'
import { onlineSales, inStoreSales } from './schema'

const onlineTransactions = db.select({ transaction: onlineSales.transactionId }).from(onlineSales);
const inStoreTransactions = db.select({ transaction: inStoreSales.transactionId }).from(inStoreSales);

const result = await unionAll(onlineTransactions, inStoreTransactions);

(select "transaction_id" from "online_sales")
union all
(select "transaction_id" from "in_store_sales")

import { onlineSales, inStoreSales } from './schema'

const result = await db
  .select({ transaction: onlineSales.transactionId })
  .from(onlineSales)
  .unionAll(
    db.select({ transaction: inStoreSales.transactionId }).from(inStoreSales)
  );

(select "transaction_id" from "online_sales")
union all
(select "transaction_id" from "in_store_sales")

import { integer, pgTable, text, timestamp, varchar } from "drizzle-orm/pg-core";

export const onlineSales = pgTable('online_sales', {
    transactionId: integer('transaction_id').primaryKey(),
    productId: integer('product_id').unique(),
    quantitySold: integer('quantity_sold'),
    saleDate: timestamp('sale_date', { mode: 'date' }),
});

export const inStoreSales = pgTable('in_store_sales', {
    transactionId: integer('transaction_id').primaryKey(),
    productId: integer('product_id').unique(),
    quantitySold: integer('quantity_sold'),
    saleDate: timestamp('sale_date', { mode: 'date' }),
});

交集

仅合并两个查询块结果中共有的行，并省略任何重复项。

假设你有两个表，存储学生课程选课信息。
你想找出两个不同院系之间共有的课程，
但你只想要不同的课程名称，并且你不关心统计同一学生对同一课程的多次
选课记录。

在这个场景中，你想找出两个院系之间共有的课程，但不希望
即使同一院系的多个学生选了同一门课，也把同一课程重复计数。

import-pattern

builder-pattern

schema.ts

import { intersect } from 'drizzle-orm/pg-core'
import { depA, depB } from './schema'

const departmentACourses = db.select({ courseName: depA.courseName }).from(depA);
const departmentBCourses = db.select({ courseName: depB.courseName }).from(depB);

const result = await intersect(departmentACourses, departmentBCourses);

(select "course_name" from "department_a_courses")
intersect
(select "course_name" from "department_b_courses")

import { depA, depB } from './schema'

const result = await db
  .select({ courseName: depA.courseName })
  .from(depA)
  .intersect(db.select({ courseName: depB.courseName }).from(depB));

(select "course_name" from "department_a_courses")
intersect
(select "course_name" from "department_b_courses")

import { integer, pgTable, varchar } from "drizzle-orm/pg-core";

export const depA = pgTable('department_a_courses', {
    studentId: integer('student_id'),
    courseName: varchar('course_name').notNull(),
});

export const depB = pgTable('department_b_courses', {
    studentId: integer('student_id'),
    courseName: varchar('course_name').notNull(),
});

交集全部

仅合并两个查询块结果中共有的那些行，并保留重复项。

假设有两个包含客户订单数据的表，你想要识别既被普通客户又被 VIP 客户订购的产品。在这种情况下，你希望跟踪每个产品的数量，即使它被不同客户多次订购。

在这个场景中，你想找到既被普通客户又被 VIP 客户订购的产品，但你希望保留数量信息，即使同一个产品被不同客户多次订购。

import-pattern

builder-pattern

schema.ts

import { intersectAll } from 'drizzle-orm/pg-core'
import { regularCustomerOrders, vipCustomerOrders } from './schema'

const regularOrders = db.select({ 
    productId: regularCustomerOrders.productId,
    quantityOrdered: regularCustomerOrders.quantityOrdered }
).from(regularCustomerOrders);

const vipOrders = db.select({ 
    productId: vipCustomerOrders.productId,
    quantityOrdered: vipCustomerOrders.quantityOrdered }
).from(vipCustomerOrders);

const result = await intersectAll(regularOrders, vipOrders);

(select "product_id", "quantity_ordered" from "regular_customer_orders")
intersect all
(select "product_id", "quantity_ordered" from "vip_customer_orders")

import { regularCustomerOrders, vipCustomerOrders } from './schema'

const result = await db
    .select({
      productId: regularCustomerOrders.productId,
      quantityOrdered: regularCustomerOrders.quantityOrdered,
    })
    .from(regularCustomerOrders)
    .intersectAll(
      db
        .select({
          productId: vipCustomerOrders.productId,
          quantityOrdered: vipCustomerOrders.quantityOrdered,
        })
        .from(vipCustomerOrders)
    );

(select "product_id", "quantity_ordered" from "regular_customer_orders")
intersect all
(select "product_id", "quantity_ordered" from "vip_customer_orders")

import { integer, pgTable } from "drizzle-orm/pg-core";

export const regularCustomerOrders = pgTable('regular_customer_orders', {
    customerId: integer('customer_id').primaryKey(),
    productId: integer('product_id').notNull(),
    quantityOrdered: integer('quantity_ordered').notNull(),
});

export const vipCustomerOrders = pgTable('vip_customer_orders', {
    customerId: integer('customer_id').primaryKey(),
    productId: integer('product_id').notNull(),
    quantityOrdered: integer('quantity_ordered').notNull(),
});

Except

对于两个查询块 A 和 B，返回 A 中所有不同时也出现在 B 中的结果，并省略任何重复项。

假设你有两张表，用于存储员工的项目分配信息。你想找出某个部门独有的项目，而不是与另一个部门共享的项目，并排除重复项。

在这个场景中，你想识别只属于一个部门且不与另一个部门共享的项目。即使同一部门的多个员工被分配到同一个项目，你也不想将同一个项目计算多次。

import-pattern

builder-pattern

schema.ts

import { except } from 'drizzle-orm/pg-core'
import { depA, depB } from './schema'

const departmentACourses = db.select({ courseName: depA.projectsName }).from(depA);
const departmentBCourses = db.select({ courseName: depB.projectsName }).from(depB);

const result = await except(departmentACourses, departmentBCourses);

(select "projects_name" from "department_a_projects")
except
(select "projects_name" from "department_b_projects")

import { depA, depB } from './schema'

const result = await db
    .select({ courseName: depA.projectsName })
    .from(depA)
    .except(db.select({ courseName: depB.projectsName }).from(depB));

(select "projects_name" from "department_a_projects")
except
(select "projects_name" from "department_b_projects")

import { integer, pgTable, varchar } from "drizzle-orm/pg-core";

export const depA = pgTable('department_a_projects', {
    employeeId: integer('employee_id'),
    projectsName: varchar('projects_name').notNull(),
});

export const depB = pgTable('department_b_projects', {
    employeeId: integer('employee_id'),
    projectsName: varchar('projects_name').notNull(),
});

Except All

对于两个查询块 A 和 B，返回 A 中所有不同时也出现在 B 中的结果，保留重复项。

让我们考虑这样一个场景：你有两张包含客户订单数据的表，并且你想要识别那些只被普通客户下单（不被 VIP 客户下单）的产品。
在这种情况下，你希望跟踪每种产品的数量，即使它被不同的普通客户多次下单。

在这个场景中，你希望找出那些只被普通客户下单、而没有被 VIP 客户下单的产品。你希望保留数量信息，即使同一种产品被不同的普通客户多次下单也是如此。

import-pattern

builder-pattern

schema.ts

import { exceptAll } from 'drizzle-orm/pg-core'
import { regularCustomerOrders, vipCustomerOrders } from './schema'

const regularOrders = db.select({ 
    productId: regularCustomerOrders.productId,
    quantityOrdered: regularCustomerOrders.quantityOrdered }
).from(regularCustomerOrders);

const vipOrders = db.select({ 
    productId: vipCustomerOrders.productId,
    quantityOrdered: vipCustomerOrders.quantityOrdered }
).from(vipCustomerOrders);

const result = await exceptAll(regularOrders, vipOrders);

(select "product_id", "quantity_ordered" from "regular_customer_orders")
except all
(select "product_id", "quantity_ordered" from "vip_customer_orders")

import { regularCustomerOrders, vipCustomerOrders } from './schema'

const result = await db
    .select({
      productId: regularCustomerOrders.productId,
      quantityOrdered: regularCustomerOrders.quantityOrdered,
    })
    .from(regularCustomerOrders)
    .exceptAll(
      db
        .select({
          productId: vipCustomerOrders.productId,
          quantityOrdered: vipCustomerOrders.quantityOrdered,
        })
        .from(vipCustomerOrders)
    );

(select "product_id", "quantity_ordered" from "regular_customer_orders")
except all
(select "product_id", "quantity_ordered" from "vip_customer_orders")

import { integer, pgTable } from "drizzle-orm/pg-core";

export const regularCustomerOrders = pgTable('regular_customer_orders', {
    customerId: integer('customer_id').primaryKey(),
    productId: integer('product_id').notNull(),
    quantityOrdered: integer('quantity_ordered').notNull(),
});

export const vipCustomerOrders = pgTable('vip_customer_orders', {
    customerId: integer('customer_id').primaryKey(),
    productId: integer('product_id').notNull(),
    quantityOrdered: integer('quantity_ordered').notNull(),
});