Drizzle 查询 + CRUD

Drizzle 提供了几种查询数据库的方法，您可以根据下一个项目的需要选择合适的方式。

它可以是类似 SQL 的语法或关系语法。让我们来看看它们：

Why choose SQL-like syntax?

If you know SQL, you can master Drizzle.

Other ORMs and data frameworks often deviate from or abstract away SQL, which creates a double learning curve: you need to learn both SQL and the framework’s API.

Drizzle is the opposite. We embrace SQL and build Drizzle’s core in a SQL-like form, so that you have almost no learning curve and can fully leverage the power of SQL.

// Access your data
await db
  .select()
	.from(posts)
	.leftJoin(comments, eq(posts.id, comments.post_id))
	.where(eq(posts.id, 10))

SELECT * 
FROM posts
LEFT JOIN comments ON posts.id = comments.post_id
WHERE posts.id = 10

With SQL-like syntax, you can do most of what you can do in plain SQL, and clearly know what Drizzle will execute and what queries it will generate. You can perform a variety of queries, including select, insert, update, delete, as well as aliases, WITH clauses, subqueries, prepared statements, and more. Let’s look at more examples.

await db.insert(users).values({ email: 'user@gmail.com' })

INSERT INTO users (email) VALUES ('user@gmail.com')

await db.update(users)
        .set({ email: 'user@gmail.com' })
        .where(eq(users.id, 1))

UPDATE users 
SET email = 'user@gmail.com'
WHERE users.id = 1

await db.delete(users).where(eq(users.id, 1))

DELETE FROM users WHERE users.id = 1

为什么不选择 SQL 类似语法？

我们始终在追求一个完美平衡的解决方案。虽然 SQL 类似查询可以满足 100% 的需求， 但在某些常见场景中，数据的查询可以更高效。

我们构建了查询 API，以便你可以以最方便和高效的方式从数据库中获取关系型、嵌套数据， 而无需担心联接或数据映射。

Drizzle 总是输出确切的一个 SQL 查询。可以放心地与无服务器数据库一起使用， 而无需担心性能或往返成本！

const result = await db.query.users.findMany({
	with: {
		posts: true
	},
});

高级

使用 Drizzle，查询可以以你想要的任何方式组合和分区。 你可以独立于主查询组合过滤器，分离子查询或条件语句，等等。 让我们来看几个高级示例：

组合一个 WHERE 语句，然后在查询中使用它

async function getProductsBy({
  name,
  category,
  maxPrice,
}: {
  name?: string;
  category?: string;
  maxPrice?: number;
}) {
  const filters: SQL[] = [];

  if (name) filters.push(ilike(products.name, name));
  if (category) filters.push(eq(products.category, category));
  if (maxPrice) filters.push(lte(products.price, maxPrice));

  return db
    .select()
    .from(products)
    .where(and(...filters));
}

将子查询分离到不同变量中，然后在主查询中使用它们

const subquery = db
	.select()
	.from(internalStaff)
	.leftJoin(customUser, eq(internalStaff.userId, customUser.id))
	.as('internal_staff');

const mainQuery = await db
	.select()
	.from(ticket)
	.leftJoin(subquery, eq(subquery.internal_staff.userId, ticket.staffId));

接下来是什么？