instruction: Number of created accounts per week.
response: SELECT (TIME_TO_STR(CreationDate, '%y') + (TIME_TO_STR(CreationDate, '%W') - 1) / 52.0) AS YR_WK, COUNT(*) AS c FROM Users GROUP BY (TIME_TO_STR(CreationDate, '%y') + (TIME_TO_STR(CreationDate, '%W') - 1) / 52.0) ORDER BY (TIME_TO_STR(CreationDate, '%y') + (TIME_TO_STR(CreationDate, '%W') - 1) / 52.0)