The result of the above SQL statement will be the number 3, because the customer Smith has made 3 orders in total. If you don't specify a WHERE clause when using COUNT, your statement will simply return the total number of rows in the table, which in our case is 7:
Uses of Sleep Spindles Edit. Sleep spindles are one of several measures employed by the brain to keep a sleeper in an unconscious state. This pattern is produced during sleep to inhibit the processing of unnecessary information, which would especially interrupt stage 2 sleep.
Stage N2 sleep is scored when either one or more K complexes is noted (and unassociated with an arousal) or one or more trains of sleep spindles appear. Stage N2. Note K complexes unassociated with arousal and trains of sleep spindles.