MySQL Workbench: I need to update values in a table based on values from a csv
Import CSV file to temporary table and then run the UPDATE. For example:

DROP TEMPORARY TABLE IF EXISTS tempTable; 
CREATE TEMPORARY TABLE tempTable
(id_inv int,
unit varchar(255),
PRIMARY KEY (id_inv)
);

LOAD DATA INFILE 'C:\\PathToYour\\FileName.csv'
INTO tempTable (id_inv, unit)
FIELDS TERMINATED BY ','
LINES TERMINATED BY '\r\n';

UPDATE DBtable t1
JOIN tempTable t2 ON t1.id_inv = t2.id_inv
SET t1.unit = t2.unit;

DROP TEMPORARY TABLE tempTable; 


You may need to use different symbols for fields and lines terminators and file path of course. Also if you are working with remote server use "LOAD DATA LOCAL INFILE" command.