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ducklake_partition_column

Partitions can refer to one or more columns, possibly with transformations such as hashing or bucketing.

Column name Column type  
partition_id BIGINT  
table_id BIGINT  
partition_key_index BIGINT  
column_id BIGINT  
transform VARCHAR  
  • partition_id refers to a partition_id from the ducklake_partition_info table.
  • table_id refers to a table_id from the ducklake_table table.
  • partition_key_index defines where in the partition key the column is using 0-based indexing. For example, in a partitioning by (a, b, c) the partition_key_index of b would be 1.
  • column_id refers to a column_id from the ducklake_column table.
  • transform defines the type of a transform that is applied to the column value, e.g., year.

The table of supported transforms is as follows.

Transform Source type(s) Description Result type
identity Any Source value, unmodified Source type
year date, timestamp, timestamptz, timestamp_s, timestamp_ms, timestamp_ns Extract a date or timestamp year, as years from 1970 int64
month date, timestamp, timestamptz, timestamp_s, timestamp_ms, timestamp_ns Extract a date or timestamp month, as months from 1970-01-01 int64
day date, timestamp, timestamptz, timestamp_s, timestamp_ms, timestamp_ns Extract a date or timestamp day, as days from 1970-01-01 int64
hour timestamp, timestamptz, timestamp_s, timestamp_ms, timestamp_ns Extract a timestamp hour, as hours from 1970-01-01 00:00:00 int64