想要查詢上月第2個周末的數據，我們需要用到一些 MySQL 的函數。這里我們將使用 WEEK() 和 DAYOFWEEK() 函數。

首先，我們需要獲取上一個月的年份和月份。可以使用以下查詢語句：

SELECT 
YEAR(CURRENT_DATE - INTERVAL 1 MONTH) AS prev_year,
MONTH(CURRENT_DATE - INTERVAL 1 MONTH) AS prev_month;

接下來，我們可以使用 WEEK() 函數來獲取上一個月的第一天和最后一天的周數。這樣我們就可以知道上一個月有多少周了。

SELECT 
WEEK(CONCAT(prev_year, '-', prev_month, '-01')) AS first_week,
WEEK(LAST_DAY(CONCAT(prev_year, '-', prev_month, '-01'))) AS last_week;

現在我們已經知道了上一個月有多少個周了，我們就可以使用 DAYOFWEEK() 函數來獲取上一個月每一天是周幾了。這樣我們就可以篩選出第 2 個周末了。

SELECT
CONCAT(prev_year, '-', prev_month, '-', DAY) AS date,
DAYNAME(CONCAT(prev_year, '-', prev_month, '-', DAY)) AS week_day,
WEEK(CONCAT(prev_year, '-', prev_month, '-', DAY)) AS week,
@cnt := IF(week = first_week AND week_day = 'Saturday', 1,
IF(week = first_week AND WEEKDAY(CONCAT(prev_year, '-', prev_month, '-01'))< 5, 1,
IF(week = first_week + 1 AND WEEKDAY(CONCAT(prev_year, '-', prev_month, '-01')) >4, 1, 0))) AS cnt,
@cnt := IF(week_day = 'Saturday' OR week_day = 'Sunday', @cnt + 1, @cnt) AS weekend_cnt
FROM (
SELECT DAY
FROM (
SELECT DAYOFMONTH(CONCAT(prev_year, '-', prev_month, '-', 1 - DAYOFWEEK(CONCAT(prev_year, '-', prev_month, '-01')) + (@num := @num + 1))) AS DAY
FROM mysql.help_topic 
JOIN (SELECT @num:=-1) num
WHERE DAY<= LAST_DAY(CONCAT(prev_year, '-', prev_month, '-01'))
) AS day_numbers
) AS days, (SELECT @cnt:=0) cnt
HAVING weekend_cnt = 2 AND cnt = 1;

以上就是獲取上月第二個周末的 MySQL 查詢語句。希望對大家有所幫助！