How to query after partitioning the Oracle table?

2 years ago
William Carter
1 minute

In Oracle, you can query data after sharding using the following methods:

  1. Combine the query results from multiple separate tables using the UNION ALL operator. For example, if there are two tables T1 and T2, you can use the following statement to query the merged data:
SELECT * FROM T1
UNION ALL
SELECT * FROM T2;
  1. Select the partitioned table to query dynamically based on expressions and conditions. For example, consider a partitioned table T, and choose which partition to query based on conditions.
SELECT * FROM T PARTITION (PARTITION_NAME) WHERE CONDITION;

Where PARTITION_NAME represents the name of the partition to be queried, and CONDITION represents the query condition.

  1. Use partitioned clauses to specify the partitions to be queried directly in the query. For example, suppose there is a partitioned table T, you can use the following statement to query the data in the specified partition:
SELECT * FROM T PARTITION (PARTITION_NAME);

In this case, PARTITION_NAME represents the name of the partition to be queried.

Please note that the specific query methods may vary due to the database design and sharding strategy. When using sharding, appropriate query methods should be chosen based on the specific situation.

bannerAds