我正在做一些 SQL 优化,但我的 SQL fu 可以使用一些改进......
为什么要对子查询进行联接,这可能只是直接的内部联接,还是我遗漏了什么?
-- Why do a join and a subquery?
-- INNER JOIN (
-- SELECT client_id, session_id, id, customer_id, validity, machine_id,
-- utc_date_completed, itemStatus, totalValue, utc_date_updated,
-- itemValue, itemId, itemName, customField1, customField2, itemPage, itemCurrency
-- FROM data.dashboard WITH(NOLOCK)
-- WHERE client_id = @client_id
-- ) d ON cm.client_id = d.client_id
INNER JOIN data.dashboard AS d ON cm.client_id = d.client_id AND d.client_id = @client_id