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Document sort direction and null order in Iceberg #24554

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Dec 21, 2024
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Document sort direction and null order in Iceberg #24554

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12 changes: 12 additions & 0 deletions docs/src/main/sphinx/connector/iceberg.md
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Expand Up @@ -1502,6 +1502,18 @@ CREATE TABLE example.customers.orders (
WITH (sorted_by = ARRAY['order_date'])
```

You can explicitly configure sort directions or null ordering in the following way:

```
CREATE TABLE example.customers.orders (
order_id BIGINT,
order_date DATE,
account_number BIGINT,
customer VARCHAR,
country VARCHAR)
WITH (sorted_by = ARRAY['order_date DESC NULLS FIRST', 'order_id ASC NULLS LAST'])
```
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@okumin okumin Dec 21, 2024

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I tested this SQL in my local machine.

trino> CREATE TABLE iceberg.default.orders (
    ->     order_id BIGINT,
    ->     order_date DATE,
    ->     account_number BIGINT,
    ->     customer VARCHAR,
    ->     country VARCHAR)
    -> WITH (sorted_by = ARRAY['order_date DESC NULLS FIRST', 'order_id ASC NULLS LAST'])
    -> ;
CREATE TABLE
trino> 

$ hdfs dfs -cat /user/hive/warehouse/orders-5fae815b97d54add91c0100370e56f0c/metadata/00000-cf46fb4f-226b-42dc-b640-c14d9e000c09.metadata.json
...
  "schemas" : [ {
    "type" : "struct",
    "schema-id" : 0,
    "fields" : [ {
      "id" : 1,
      "name" : "order_id",
      "required" : false,
      "type" : "long"
    }, {
      "id" : 2,
      "name" : "order_date",
      "required" : false,
      "type" : "date"
    }, {
      "id" : 3,
      "name" : "account_number",
      "required" : false,
      "type" : "long"
    }, {
      "id" : 4,
      "name" : "customer",
      "required" : false,
      "type" : "string"
    }, {
      "id" : 5,
      "name" : "country",
      "required" : false,
      "type" : "string"
    } ]
  } ],
...
  "default-sort-order-id" : 1,
  "sort-orders" : [ {
    "order-id" : 1,
    "fields" : [ {
      "transform" : "identity",
      "source-id" : 2,
      "direction" : "desc",
      "null-order" : "nulls-first"
    }, {
      "transform" : "identity",
      "source-id" : 1,
      "direction" : "asc",
      "null-order" : "nulls-last"
    } ]
  } ],


Sorting can be combined with partitioning on the same column. For example:

```
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