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.
Although not required for scoring, sleep spindles may persist in stage N3 sleep. Also, K complexes may also be present but would be considered as slow waves if they meet the above definition of slow wave activity. Eye movements are unusual in this stage and are typically not seen.