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      • PostgreSQL UPDATE / PostgreSQL更新数据 / PostgreSQL UPDATE / PostgreSQL更新数据

      PostgreSQL UPDATE / PostgreSQL更新数据

      Overview / 概述

      The UPDATE statement modifies existing records in a table. This chapter covers how to update single or multiple columns and use conditions.

      UPDATE语句修改表中的现有记录。本章介绍如何更新单列或多列以及使用条件。

      Basic UPDATE / 基本更新

      Update Single Column / 更新单列

      UPDATE users SET status = 'active' WHERE id = 1;

      Update Multiple Columns / 更新多列

      UPDATE users SET 
    first_name = 'John',
    last_name = 'Doe',
    email = 'john.doe@example.com'
WHERE id = 1;

      UPDATE with WHERE / 带条件的更新

      -- Update specific row
UPDATE users SET status = 'inactive' WHERE id = 5;

-- Update multiple rows
UPDATE products SET price = price * 1.1 WHERE category = 'Electronics';

-- Update with IN
UPDATE users SET status = 'vip' WHERE id IN (1, 2, 3, 4, 5);

      UPDATE with RETURNING / 返回更新结果

      UPDATE users SET last_login = NOW() WHERE id = 1
RETURNING id, name, last_login;

      UPDATE with Subquery / 使用子查询更新

      -- Update based on subquery
UPDATE products SET price = (
    SELECT AVG(price) FROM products WHERE category_id = products.category_id
) WHERE price IS NULL;

      Summary / 小结

      UPDATE statement:

      • Modify existing records
      • Use WHERE to filter rows
      • Update single or multiple columns
      • RETURNING to get updated values