Live aggregate projection

Stores the grouped results of queries that invoke aggregate functions (such as SUM) on table columns.

Stores the grouped results of queries that invoke aggregate functions (such as SUM) on table columns. For details, see Live aggregate projections.

Syntax

CREATE PROJECTION [ IF NOT EXISTS ] [[database.]schema.]projection
[ (
   { projection-column | grouped-clause
   [ ENCODING encoding-type ]
   [ ACCESSRANK integer ] }[,...]
) ]
AS SELECT { table-column | expr-with-table-columns }[,...] FROM [[database.]schema.]table [ [AS] alias]
   GROUP BY column-expr
   [ KSAFE [ k-num ] ]

Parameters

IF NOT EXISTS

If an object with the same name exists, return without creating the object. If you do not use this directive and the object already exists, Vertica returns with an error message.

The IF NOT EXISTS clause is useful for SQL scripts where you might not know if the object already exists. The ON ERROR STOP directive can be helpful in scripts.

[database.]schema

Specifies the schema for this projection and its anchor table, where schema must be the same for both. If you specify a database, it must be the current database.

projection

Identifies the projection to create, where projection conforms to conventions described in Identifiers. It must also be unique among all names of sequences, tables, projections, views, and models within the same schema.

projection-column

The name of a projection column. The list of projection columns must match the SELECT list columns and expressions in number, type, and sequence.

If projection column names are omitted, Vertica uses the anchor table column names specified in the SELECT list.

grouped-clause

See GROUPED clause.

ENCODING encoding-type

The column encoding type, by default set to AUTO.

ACCESSRANK integer

Overrides the default access rank for a column. Use this parameter to increase or decrease the speed at which Vertica accesses a column. For more information, see Overriding Default Column Ranking.

AS SELECT

Specifies the table data to query:

{table-column | expr-with-table-columns } [ [AS] alias] }[,...]

You can optionally assign an alias to each column expression and reference that alias elsewhere in the SELECT statement.

Note

If you specify projection column names, the two lists of projection columns and table columns/expressions must exactly match in number and order.

GROUP BY column-expr[,...]

One or more column expressions from the SELECT list. The first column-expr must be the first column expression in the SELECT list, the second column-expr must be the second column expression in the SELECT list, and so on.

Privileges

Non-superusers:

Anchor table owner
CREATE privilege on the schema

Requirements and restrictions

Vertica does not regard live aggregate projections as superprojections, even those that include all table columns. For other requirements and restrictions, see Creating live aggregate projections.

Examples

See Live aggregate projection example.