Rick Debay wrote:
I notice that NOW is usually later than CURRENT_TIMESTAMP. I believe this has to do with transactions, but I'd like an explanation.
Ann W. Harrison answers:
NOW is the time at the instant it is evaluated. CURRENT_TIMESTAMP is fixed for the duration of a statement. In other words, if you were to update every record in a large table, setting TIME_MODIFIED to NOW, you'd see several different times. CURRENT_TIMESTAMP, on the other hand, would set the TIME_MODIFIED to the same value.