Update (Delta Lake on Databricks) 

UPDATE [db_name.]table_name [AS alias] SET col1 = value1 [, col2 = value2 ...] [WHERE predicate]

Update the column values for the rows that match a predicate. When no predicate is provided, update the column values for all rows.

Note

(Delta Lake on Databricks) If a column has a NOT NULL constraint, and an INSERT INTO statement sets a column value to NULL, a SparkException is thrown.

WHERE

Filter rows by predicate.

Example 

UPDATE events SET eventType = 'click' WHERE eventType = 'clk'

UPDATE supports subqueries in the WHERE predicate, including IN, NOT IN, EXISTS, NOT EXISTS, and scalar subqueries.

Subquery Examples 

UPDATE all_events
  SET session_time = 0, ignored = true
  WHERE session_time < (SELECT min(session_time) FROM good_events)

UPDATE orders AS t1
  SET order_status = 'returned'
  WHERE EXISTS (SELECT oid FROM returned_orders WHERE t1.oid = oid)

UPDATE events
  SET category = 'undefined'
  WHERE category NOT IN (SELECT category FROM events2 WHERE date > '2001-01-01')

Note

The following types of subqueries are not supported:

  • Nested subqueries, that is, a subquery inside another subquery

  • A NOT IN subquery inside an OR, for example, a = 3 OR b NOT IN (SELECT c from t)

In most cases, you can rewrite NOT IN subqueries using NOT EXISTS. We recommend using NOT EXISTS whenever possible, as UPDATE with NOT IN subqueries can be slow.