用mysql的limit進行分頁。。發現竟然有些數據沒顯示在頁面上。。總共才24條數據。楞找不到。。
后來把語句弄到mysql上查了一下才知道。這條語句中的limit有問題。。有些數據在第二頁被重復顯示了。。
非常郁悶。。下面給截圖
查第一頁的語句
- SQL code
-
SELECT * FROM article a where a.type in (1,2,4) limit 0,20;
第一頁的結果
 (注意紅色部分)
第二頁的語句
- SQL code
-
SELECT * FROM article a where a.type in (1,2,4) limit 20,20;
結果：
 (注意紅色部分)
--------------------------------------------------------------------------
后來發現排下序就沒事了。。原來用MySQL的limit必須排序。。唉
這是一位網友給的MySQL Help:
If you use LIMIT row_count with ORDER BY, MySQL ends the sorting as
soon as it has found the first row_count rows of the sorted result,
rather than sorting the entire result. If ordering is done by using an
index, this is very fast. If a filesort must be done, all rows that
match the query without the LIMIT clause must be selected, and most or
all of them must be sorted, before it can be ascertained that the first
row_count rows have been found. In either case, after the initial rows
have been found, there is no need to sort any remainder of the result
set, and MySQL does not do so.
..用limit必須排序，，切記切記...
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