ความถี่ของคำสำคัญ สัปดาห์ต่อสัปดาห์ ไม่จำเป็นต้องใช้ตารางทั้งหมด
Frequency of a keyword, week by week.It is not neccessary to use all the tables.
 PostTypes:  Id [ number]  Name [ text] 
SELECT CAST(TIME_TO_STR(CreationDate, '%Y') AS TEXT(4)) + '-week' + CAST(TIME_TO_STR(CreationDate, '%W') AS TEXT(2)), COUNT(*) AS freq FROM Posts WHERE Posts.PostTypeId = 1 AND Body LIKE '%<' + LOWER(@keyword) + '>%' GROUP BY TIME_TO_STR(CreationDate, '%Y'), TIME_TO_STR(CreationDate, '%W') ORDER BY TIME_TO_STR(CreationDate, '%Y'), TIME_TO_STR(CreationDate, '%W')