Merge pull request #66163 from Blargian/docs_partitionID

Add alias `partitionID` for function `partitionId` and add documentation

docs/en/sql-reference/functions/other-functions.md

@@ -2984,6 +2984,66 @@ Result:
 └─────────┘
 ```
 
+## partitionID
+
+Computes the [partition ID](../../engines/table-engines/mergetree-family/custom-partitioning-key.md).
+
+:::note
+This function is slow and should not be called for large amount of rows.
+:::
+
+**Syntax**
+
+```sql
+partitionID(x[, y, ...]);
+```
+
+**Arguments**
+
+- `x` — Column for which to return the partition ID.
+- `y, ...` — Remaining N columns for which to return the partition ID (optional).
+
+**Returned Value**
+
+- Partition ID that the row would belong to. [String](../data-types/string.md).
+
+**Example**
+
+Query:
+
+```sql
+DROP TABLE IF EXISTS tab;
+
+CREATE TABLE tab
+(
+  i int,
+  j int
+)
+ENGINE = MergeTree
+PARTITION BY i
+ORDER BY tuple();
+
+INSERT INTO tab VALUES (1, 1), (1, 2), (1, 3), (2, 4), (2, 5), (2, 6);
+
+SELECT i, j, partitionID(i), _partition_id FROM tab ORDER BY i, j;
+```
+
+Result:
+
+```response
+┌─i─┬─j─┬─partitionID(i)─┬─_partition_id─┐
+│ 1 │ 1 │ 1              │ 1             │
+│ 1 │ 2 │ 1              │ 1             │
+│ 1 │ 3 │ 1              │ 1             │
+└───┴───┴────────────────┴───────────────┘
+┌─i─┬─j─┬─partitionID(i)─┬─_partition_id─┐
+│ 2 │ 4 │ 2              │ 2             │
+│ 2 │ 5 │ 2              │ 2             │
+│ 2 │ 6 │ 2              │ 2             │
+└───┴───┴────────────────┴───────────────┘
+```
+
+
 ## shardNum
 
 Returns the index of a shard which processes a part of data in a distributed query. Indices are started from `1`.

src/Functions/partitionId.cpp

@@ -66,6 +66,7 @@ public:
 REGISTER_FUNCTION(PartitionId)
 {
     factory.registerFunction<FunctionPartitionId>();
+    factory.registerAlias("partitionID", "partitionId");
 }
 
 }

tests/integration/test_lost_part/test.py

@@ -266,7 +266,7 @@ def test_lost_last_part(start_cluster):
             "ALTER TABLE mt3 UPDATE id = 777 WHERE 1", settings={"mutations_sync": "0"}
         )
 
-        partition_id = node1.query("select partitionId('x')").strip()
+        partition_id = node1.query("select partitionID('x')").strip()
         remove_part_from_disk(node1, "mt3", f"{partition_id}_0_0_0")
 
         # other way to detect broken parts

tests/queries/0_stateless/01748_partition_id_pruning.sql

@@ -8,17 +8,17 @@ insert into x values (1, 1), (1, 2), (1, 3), (2, 4), (2, 5), (2, 6);
 
 set max_rows_to_read = 3;
 
-select * from x where _partition_id = partitionId(1);
+select * from x where _partition_id = partitionID(1);
 
 set max_rows_to_read = 5; -- one row for subquery + subquery
 
-select * from x where _partition_id in (select partitionId(number + 1) from numbers(1));
+select * from x where _partition_id in (select partitionID(number + 1) from numbers(1));
 
 -- trivial count optimization test
 set max_rows_to_read = 2; -- one row for subquery + subquery itself
 -- TODO: Relax the limits because we might build prepared set twice with _minmax_count_projection
 set max_rows_to_read = 3;
-select count() from x where _partition_id in (select partitionId(number + 1) from numbers(1));
+select count() from x where _partition_id in (select partitionID(number + 1) from numbers(1));
 
 drop table x;
 

utils/check-style/aspell-ignore/en/aspell-dict.txt

@@ -2200,6 +2200,8 @@ parseReadableSizeOrZero
 parseTimeDelta
 parseable
 parsers
+partitionId
+partitionID
 pathFull
 pclmulqdq
 pcre