"The best way to provide this functionality is to combine a unique index with a filtered index."

It looks like you forgot (deliberately?) to include the code to create this index...

Hi - nice idea (I wasn't aware of that particular issue), but no - the script is far smaller than 1MB.

It gets even stranger; if we add the following ...

... statements ...

GO

PRINT 'Unpredictable application behaviour is the bane of my life' <-----------------------------------

UPDATE <table1>

SET <table1>.<field1> = <table2>.<field1>,

<table1>.<field2> = 'blah'

FROM <table2>

WHERE...