I just upgraded one of my test installations to the latest HEAD code, from some previous 1.5 development code (about 3 months old I guess).
This upgrading line hit:
(mysql): ALTER TABLE mdl_workshop CHANGE deadline submissionend INTEGER(10) UNSIGNED DEFAULT '0' NOT NULL AFTER `assessmentstart`
1064: You have an error in your SQL syntax near 'AFTER `assessmentstart`' at line 1
And after that there was a whole mess of failed commands, but it was all an avalanche effect starting from this.
I 'm reporting this as I have no time to investigate right now myself... any takers?