WebMay 27, 2024 · 影响执行计划的一个因素是 limit,因此order by 使用和不使用查询limit可能会返回不同顺序的行。 如果确保使用和不使用相同的行顺序很重要, 请LIMIT在ORDER BY … WebIt will still be sorted in descending order, and we are not satisfied with that, so we ask mysql to sort it one more time. Now we have the newest result on the last row. select t.article from (select article, publish_date from table1 order by publish_date desc limit 10) t order by t.publish_date asc;
order by 字段到底要不要加索引?[大坑] - 腾讯云
WebApr 2, 2024 · 1.order by limit 选错索引示例在日常工作中,经常发现一些简单的查询语句因为加了 order by limit 造成优化器选择索引错误。例如如下sql(此处就不造数据了,只是列出 … WebOct 10, 2024 · order by和limit一起使用,避免引起全表扫描和数据排序是非常重要的,因此借助合适的索引提高查询效率。 使用联合索引 联合索引又叫复合索引,是由表中的几个列 … texas wholesalers
order by limit 造成优化器选择索引错误 - CSDN博客
Web三、其他order by 索引失效的原因分析. 1、MySQL每天一条简单语句只应用一个索引,所以order by的字段要在索引之中,并且和where条件可以合并成组合索引。. 2、select的字段,必须是索引字段。. (主键查询除外). 3、如果sql语句为复合语句,包含子查询等,可以把 ... WebSep 8, 2024 · 对于带有order by或group by和limit子句的查询,优化器会在默认情况下尝试选择有序索引,因为这样做可以加快查询的执行速度。在mysql 8.0.21之前,没有办法覆盖 … Web2 days ago · To ensure timely compliance, taxpayers in this category will not be allowed to report invoices older than 7 days on the date of reporting. 3. Please note that this restriction will only apply to the document type invoice, and there will be no time restriction on reporting debit/credit notes. 4. For example, if an invoice has a date of April 1 ... texas wholesale real estate