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      • PostgreSQL UPDATE

      Overview

      Overview

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

      Update Single Column

      Update Single Column

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

      Update Multiple Columns

      Update Multiple Columns

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

      UPDATE with WHERE

      UPDATE with WHERE

      -- 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

      UPDATE with RETURNING

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

      UPDATE with Subquery

      UPDATE with Subquery

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

      PostgreSQL UPDATE

      UPDATE statement:

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