Subject Written By Posted order by 2 columns avancha mailto November 01, 2012 09:18PM Re: order by 2 columns laptop alias November 02, 2012 01:19AM Sorry, you can't reply to this topic. It has been closed.
If multiple rows have identical values in theORDER BYcolumns, the server is free to return those rows in any order, and may do so differently depending on the overall execution plan. In other words, the sort order of those rows is nondeterministic with respect to the nonordered columns. On...
SELECT column1, column2, ... FROM table_name ORDER BYcolumn_name[ASC|DESC];其中，ORDER BY 子...
作为一个云计算领域的专家,我可以帮助您解决关于按两列排序MySQL表的问题。 首先,要对MySQL表进行排序,您需要使用`ORDER BY`子句。`ORDER BY`子句允许您根据一个或多个列对查询...
In other words, the sort order of those rows is nondeterministic with respect to the nonordered columns. 如果多个行在ORDER BY列中具有相同的值,则服务器可以自由地以任何顺序返回这些行,并且可以根据总体执行计划以不同的方式返回。换句话说,相对于无序列,这些行的排序顺序是不确定的。 LIMIT 和 ORDER ...
ORDER BY userid; MySQL会直接遍历上图userid索引的叶子节点链表,不需要进行额外的排序操作。这就是用索引扫描来排序。 但如果userid字段上没有任何索引,图1的B+树结构不存在,MySQL就只能先扫表筛选出符合条件的数据,再将筛选结果根据userid排序。这个排序过程就是filesort。
结论:当我们需要按照多个字段排序时,我们需要显式的指出每个字段的排序方式。...1.下面两条语句的结果是一样的 SELECT *from issue_info ORDER BY create_time ,issue_type DESC SELECT *from issue_info...ORDER BY create_...
二order by有相同,不能保证id排序 mysql文档有说明 If multiple rows have identical values in the ORDER BY columns, the server is free to return those rows in any order, and may do so differently depending on the overall execution plan. In other words, the sort order of those rows is ...
You can do that by declaring those columns as the leading columns of the PRIMARY KEY of your table. You can create a UNIQUE INDEX on the id column. 1 2 3 4 5 6 7 8 9 10 CREATE TABLE `tableMain` ( `id` INT(11) NOT NULL AUTO_INCREMENT , `value1` VARCHAR(45) NOT NULL , ...
I wonder how I can get a query to be ordered by the maximum value out of 2 columns. select column1,column2 from tbl order by ? (max of column1,columt2) Any suggestions? Subject Written By Posted order by max of two columns