mysql-database-update.php

// Copy-column.sql
UPDATE `table1` SET
`table1`.`col` = (SELECT `table2`.`col` FORM `table2` where `table1`.`ID` = `table2`.`fid`)

// REPLACE
UPDATE table SET col = REPLACE(col,',','')

// TRIM
UPDATE table SET col = TRIM(col);

// SUM with GROUP BY
SELECT col_1, SUM (col_2) FROM orders GROUP BY col_3;