Deleting rows from a Delta Lake table

This section explains how to delete rows from a Delta Lake table.

Suppose you have the following Delta table with four rows:

+-------+----------+
|   num | letter   |
|-------+----------|
|     1 | a        |
|     2 | b        |
|     3 | c        |
|     4 | d        |
+-------+----------+

Here's how to delete all the rows where the num is greater than 2:

PythonRust

dt = DeltaTable("tmp/my-table")
dt.delete("num > 2")

let delta_path = Url::from_directory_path("/tmp/some-table").unwrap();
let mut table = open_table(delta_path).await?;
let (table, delete_metrics) = DeltaOps(table)
    .delete()
    .with_predicate(col("num").gt(lit(2)))
    .await?;

with_predicate expects an argument that can be translated to a Datafusion Expression. This can be either using the Dataframe API, or using a SQL where clause:

let table = deltalake::open_table(delta_path).await?;
let (table, delete_metrics) = DeltaOps(table)
    .delete()
    .with_predicate("num > 2")
    .await?;

Here are the contents of the Delta table after the delete operation has been performed:

+-------+----------+
|   num | letter   |
|-------+----------|
|     1 | a        |
|     2 | b        |
+-------+----------+

dt.delete() accepts any SQL where clause. If no predicate is provided, all rows will be deleted.

In Rust, delete_metrics.num_deleted_rows is an Option<usize>. Row rewrite deletes report Some(count). Metadata only full file deletes also report Some(count) when this library can derive it from file metadata, and None when the exact count is unavailable without scanning data files.