Using Logical Comparators

There are are many ways to compare data in Tamr. These comparators are most often used in JOIN and FILTER statements and case expressions.

Syntax	Data Types	Example	Explanation
IS NULL	Any	state IS NULL	Returns `true` when “state” is a true `null` value.
IS NOT NULL	Any	state IS NOT NULL	Returns `true` when “state” is anything other than a true `null` value.
IS EMPTY	Any	state IS EMPTY	Returns `true` when “state” is a true `null` value, a blank string (a string with no content`''` or a string containing only whitespace characters like spaces and tabs `' '`), an empty array (`[]`), or an array containing only blank strings and true nulls (`[' ', null]`)
IS NOT EMPTY	Any	state IS NOT EMPTY	Returns `true` when “state” is anything other than a true `null` value, a blank string a string with no content`''` or a string containing only whitespace characters like spaces and tabs `' '`), an empty array (`[]`), or an array containing only blank strings and true nulls (`[' ', null]`)
==	Any	state == 'MA'	Returns `true` when “state” is equal to `'MA'`
=	Any	state = 'MA'	Returns `true` when “state” is equal to `'MA'`
!=	Any	state != 'MA'	Returns `true` when “state” is not equal to `'MA'`
>	Any Numeric	cost > 10.0	Returns `true` when “cost” is greater than 10.0
>=	Any Numeric	cost >= 10.0	Returns `true` when “cost” is greater than or equal to 10.0
<	Any Numeric	cost < 10.0	Returns `true` when “cost” is less than 10.0
<=	Any Numeric	cost <= 10.0	Returns `true` when “cost” is less than or equal to 10.0

Logical comparisons can be modified using NOT to reverse its logic. Logical conditions can also be combined with AND and OR.

Examples:
Keep (filter down to) rows that have a populated "company_name" or have a populated parent_company_name:

FILTER company_name IS NOT EMPTY OR parent_company_name IS NOT EMPTY;

Lookup the exchange rate of a currency for a given year by matching on exact values in the year and currency columns

LOOKUP exchange_rate
FROM "currency_exchange.csv" AS currency_lookup
ON year == currency_lookup.year AND currency == currency_lookup.currency;

Create a new attribute "price_in_words", set it to 'expensive' when the price is greater than 100. Otherwise, set it to 'cheap':

SELECT *,
CASE 
WHEN price > 100 THEN 'expensive' 
ELSE 'cheap' 
END AS price_category;