#!/bin/bash ## ## create table t1 and t2 (identical definition): ## mysql -B test <<'EOF' drop table if exists t1; drop table if exists t2; CREATE TABLE t1 ( `knr` int(11) unsigned default NULL, `em` varchar(255) default NULL, UNIQUE KEY `knr` (`knr`), KEY `em` (`em`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_german2_ci; CREATE TABLE t2 like t1; EOF ## ## fill table with data: ## max=100 i=0 while [ $i -lt $max ] ; do i=$(($i + 1)) echo "insert into t1 values ($i, 'em$i');" echo "insert into t2 values ($i, 'em$i');" done | mysql -B test ## ## loop endless updates: ## ## print a dot on every update to have some progress indicator. ## while true ; do mysql test -e "UPDATE t2 INNER JOIN t1 USING(knr) SET knr = NULL WHERE t1.em <> t2.em" echo -n . done exit 0