Recently, I was checking the apache error logs of a project I was working on and found that it has lot of 404 errors for images. I used my apache error parsing script and found that most of the errors were because the production db was still having some references to images present in the stage machine.
I had to do a quick find and replace in the MySQL db and after a quick search came up with the following query, using the replace function.
UPDATE table SET field = REPLACE(field, 'stage-url', 'prod-url');
Since I was about to run this query on a prod db directly, I wanted to add another condition to replace only rows that contained the stage url as an additional precaution (of course after taking backup of the db 
).
UPDATE table SET field = REPLACE(field, 'stage-url', 'prod-url') WHERE INSTR(field, 'stage-url') > 0;
Hope this query is useful for someone who also had a shock like me when they looked at the apache error logs
very elegant example of subquery. so short and useful code. thanks
Nice to know that you liked it