Partition name selection

Question

hi
i have a table tab1 with 10 partitions, and partition key being year , and partition names goes like year0304, year0405 and so on....
can i use SELECT STATEMENT in which the keyword PARTITION(PARTITION_NAME) be substituted dynamically , by intializing it to some variable like
part := 'PARTITION('||PART_YEAR||')';
where PART_YEAR is a variable which gets value through some function as year0304, year0405.....
And ultimately using it as
sql> select * from tab1 part where x =something;
i did tried but the query is treating the PART as some table alias.
any suggestions, pls help me
regards
srinivas

Answer 1

If the object is analyzed and predicate demands it, Oracle will automatically use the required partition.
In the example below Oracle automatically uses the correct partition based on the predicate (look at Pstart and Pstop columns):
SQL> create table part(
  2   part_key varchar2(10))
  3  partition by range
  4  (part_key)
  5  (partition part_#1 values less than ('C'),
  6   partition part_#2 values less than ('H'),
  7   partition part_#3 values less than ('Z'),
  8   partition part_#4 values less than (MAXVALUE)
  9  )
10  /
Table created.
SQL> BEGIN
  2      FOR idx IN ascii('A') .. ascii('Z')
  3      LOOP
  4          INSERT INTO part VALUES (chr(idx));
  5      END LOOP;
  6  END;
  7  /
PL/SQL procedure successfully completed.
SQL>
SQL> analyze table part compute statistics for table for all indexes for all indexed columns ;
Table analyzed.
SQL>
SQL> explain plan for select * from part where part_key = 'G' ;
Explained.
SQL> @?\rdbms\admin\utlxpls
PLAN_TABLE_OUTPUT
| Id  | Operation            |  Name       | Rows  | Bytes | Cost  | Pstart| Pstop |
|   0 | SELECT STATEMENT     |             |     1 |     5 |     2 |       |       |
|*  1 |  TABLE ACCESS FULL   | PART        |     1 |     5 |     2 |     2 |     2 |
Predicate Information (identified by operation id):
PLAN_TABLE_OUTPUT
   1 - filter("PART"."PART_KEY"='G')
Note: cpu costing is off
14 rows selected.
SQL>