UPDATE table_name
SET variable = 'changed field', variable = 'another changed field'
WHERE firstline_name = 1;

UPDATE `table1` AS `dest`, ( SELECT * FROM `table2` WHERE `id` = x ) AS `src`
SET `dest`.`col1` = `src`.`col1`
WHERE `dest`.`id` = x
;

UPDATE [LOW_PRIORITY] [IGNORE] table_name
SET column_name1 = expr1, column_name2 = expr2, ...
[WHERE condition];

-- Things in brackets are optional
-- IGNORE modifier updates rows even if errors occur (ie: the rows that cause errors are simply not updated)
UPDATE [IGNORE] table_name
SET column_name1 = expr1, column_name2 = expr2, ...
[WHERE condition]; -- WHERE tells us which rows to update based on said condition

UPDATE tableA a
INNER JOIN tableB b ON a.name_a = b.name_b
SET validation_check = if(start_dts > end_dts, 'VALID', '')
-- where clause can go here

UPDATE Customers SET City='Oslo'

UPDATE table_name SET column1=value1, column2=value2 WHERE condition

UPDATE Table_name
-- The desired value
SET Column_name = desired_value
-- Any value, of the item, of which one value you want to change
WHERE Column_name = value

UPDATE table_name SET field1 = new-value1, field2 = new-value2
[WHERE Clause]

CREATE TABLE copy LIKE original;
ALTER TABLE copy DISABLE KEYS;
SET unique_checks=0; SET foreign_key_checks=0;
INSERT INTO copy SELECT * FROM original;
ALTER TABLE copy ENABLE KEYS;
SET unique_checks=1; SET foreign_key_checks=1;