This topic describes the syntax of the HG_SHARD_ID_FOR_DISTRIBUTION_KEY function in Hologres.

Introduction

HG_SHARD_ID_FOR_DISTRIBUTION_KEY: queries the ID of the shard that consists of the specified key or composite key.

Synopsis

SELECT HG_SHARD_ID_FOR_DISTRIBUTION_KEY ( tablename [, column [...] ] )

Parameters

  • tablename: the name of the table for which you want to query the shard.
  • column: the key or composite key used to generate a shard.

Example

The following example queries the ID of the shard based on the composite key that contains the ORDERSKEY and CUSKEY fields:

CALL HG_SHARD_ID_FOR_DISTRIBUTION_KEY ( ORDERS, 'ORDERSKEY', 'CUSKEY' );