如何在MySQL中找到周数的周开始日期？

Question

我有一组销售数字，我试图按周排名。查询效果很好，除了我最后得到一个周数。如何将周数转换为周日期的开头？

SELECT 

SUM(`Sales`) `Record`,
Week(`DateTime of Sale`),
'Sales Record' AS `Category`,
'Weekly' AS `Interval`

FROM `SalesTable`

GROUP BY 
DATE(`DateTime of Sale`)

ORDER BY  SUM(`Sales`) DESC 

LIMIT 2