Aggregate functions - Amazon Simple Storage Service
SUM example
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Aggregate functions

Important

Amazon S3 Select is no longer available to new customers. Existing customers of Amazon S3 Select can continue to use the feature as usual. Learn more

Amazon S3 Select supports the following aggregate functions.

Function

Argument type

Return type

AVG(expression)

INT, FLOAT, DECIMAL

DECIMAL for an INT argument, FLOAT for a floating-point argument; otherwise the same as the argument data type.

COUNT

-

INT

MAX(expression)

INT, DECIMAL

Same as the argument type.

MIN(expression)

INT, DECIMAL

Same as the argument type.

SUM(expression)

INT, FLOAT, DOUBLE, DECIMAL

INT for an INT argument, FLOAT for a floating-point argument; otherwise, the same as the argument data type.

SUM example

To aggregate the total object sizes of a folder in an S3 Inventory report, use a SUM expression.

The following S3 Inventory report is a CSV file that's compressed with GZIP. There are three columns.

  • The first column is the name of the S3 bucket (DOC-EXAMPLE-BUCKET) that the S3 Inventory report is for.

  • The second column is the object key name that uniquely identifies the object in the bucket.

    The example-folder/ value in the first row is for the folder example-folder. In Amazon S3, when you create a folder in your bucket, S3 creates a 0-byte object with a key that's set to the folder name that you provided.

    The example-folder/object1 value in the second row is for the object object1 in the folder example-folder.

    The example-folder/object2 value in the third row is for the object object2 in the folder example-folder.

    For more information about S3 folders, see Organizing objects in the Amazon S3 console by using folders.

  • The third column is the object size in bytes.

"DOC-EXAMPLE-BUCKET","example-folder/","0"
"DOC-EXAMPLE-BUCKET","example-folder/object1","2011267"
"DOC-EXAMPLE-BUCKET","example-folder/object2","1570024"

To use a SUM expression to calculate the total size of the folder example-folder, run the SQL query with Amazon S3 Select.

SELECT SUM(CAST(_3 as INT)) FROM s3object s WHERE _2 LIKE 'example-folder/%' AND _2 != 'example-folder/';

Query Result: 

3581291