HASH

Overview

The Hash operation allows you to hash one or more columns using a hash algorythm.

Syntax

Applies a hash algorythm to all the values of one or more columns.

HASH COLUMNS '<field>{,...}' 
USING < MD5 | SHA1 | SHA256 | SHA384 | SHA512 >
	{ < ASCII | UTF8 | UNICODE > }
{ WITH 
	TRUNCATE
}
;

COLUMNS	Comma-separated list of columns to hash
HASH	The hashing algorythm to use (MD5,SHA1,SH256,SHA384,SHA512)
ENCODING	The encoding to use when calculating the hash value (ASCII,UTF8,UNICODE)
TRUNCATE	Truncates the hash value if necessary to match the original length of the column

Example 1

-- This HTTP request uses the Rss Feed connection and calls the /econi.xml relative URL

SELECT * FROM HTTP [Rss Feed] (GET /econi.xml) APPLY TX (//item);

APPLY PIPELINE (
		-- Hash the title field using SHA1 
		HASH COLUMNS 'title' USING SHA1;
	);

Example 2

-- This HTTP request uses the Rss Feed connection and calls the /econi.xml relative URL

SELECT * FROM HTTP [Rss Feed] (GET /econi.xml) APPLY TX (//item);

APPLY PIPELINE (
		-- Hash the title and category fields using SHA256 with UTF8 encoding and truncate the hash values generated if necessary
		-- to match the original field length
		-- In this example, multiple fields are specified for hashing
		HASH COLUMNS 'title, [category]' USING SHA256 UTF8 WITH TRUNCATE;
	);