MaxCompute:MAX_PT

Usage notes

• You can also use a standard SQL statement instead of the statement in which the MAX_PT function is used. For example, you can use select * from table where pt = (select max(pt) from table); instead of select * from table where pt = max_pt("table");.

  Note

  MaxCompute does not provide the MIN_PT function. If you need to obtain the partition that contains the fewest amount of data in a partitioned table, you cannot use the SQL statement select * from table where pt = min_pt("table");. Instead, you can use the standard SQL statement select * from table where pt = (select min(pt) from table); to achieve a similar effect as the MAX_PT function.

• If all partitions in the table are empty, the MAX_PT function fails to be executed. You must make sure that at least one partition is not empty.

• OSS external tables do not support the MAX_PT function.

Syntax

max_pt(<table_full_name>)

Parameters

table_full_name: required. A value of the STRING type. This parameter specifies the name of the table. You must have read permissions on the table.

Return value

The name of the largest level-1 partition is returned.

Examples

• Example 1: The tbl table is a partitioned table. The partitions in the table are 20120901 and 20120902, both of which contain data. If you execute the following statement, the MAX_PT function returns '20120902', and the MaxCompute SQL statement reads data from the 20120902 partition. Sample statements:

  select * from tbl where pt=max_pt('myproject.tbl');
  -- The preceding statement is equivalent to the following statement: 
  select * from tbl where pt = (select max(pt) from myproject.tbl);

• Example 2: If a partitioned table contains multiple levels of partitions, use the standard SQL statement to obtain data from the largest partition. Sample statement:

  select * from table where pt1 = (select max(pt1) from table) and pt2 = (select max(pt2) from table where pt1 = (select max(pt1) from table));

Related functions

For more information, see Other functions.