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mysql中允许多少order by列,类似于group by?_Mysql_Database_Sql Order By - Fatal编程技术网

mysql中允许多少order by列,类似于group by?

mysql中允许多少order by列,类似于group by?,mysql,database,sql-order-by,Mysql,Database,Sql Order By,我想知道我可以在“order by”子句中使用多少列,例如,我有一个列名称asc、开始日期asc、SKU组asc,并且想在order子句中添加SKU名称asc。我目前正在使用1个groupby,但出于好奇,MySQL中可以使用多少个 SELECT pop.SUB_ELEMENT, pop.NAME, sub_element.LDESC AS SUB_NAME, DATE_FORMAT(journey_visits.START_DATE, '%b %d %Y %h:%i %p' ) AS STAR

我想知道我可以在“order by”子句中使用多少列,例如,我有一个列名称asc、开始日期asc、SKU组asc,并且想在order子句中添加SKU名称asc。我目前正在使用1个groupby,但出于好奇,MySQL中可以使用多少个

SELECT pop.SUB_ELEMENT, pop.NAME, sub_element.LDESC AS SUB_NAME, DATE_FORMAT(journey_visits.START_DATE, '%b %d %Y %h:%i %p' ) AS START_DATE, visit_sku.IS_CHECK,visit_sku.TYPE AS `SKU_TYPE`,brand.LDESC AS `SKU_GROUP`,sku.LDESC AS `SKU_NAME`,sku.SKU AS `MATERIAL` FROM visit_sku 
LEFT JOIN journey_visits  ON journey_visits.VISIT_ID = visit_sku.VISIT_ID 
LEFT JOIN pop ON journey_visits.POP_ID = pop.POPID
LEFT JOIN sub_element ON sub_element.SubElementID=pop.SUB_ELEMENT
LEFT JOIN sku ON visit_sku.SKU_ID = visit_sku.SKU_ID AND visit_sku.SKU_ID = sku.SKU  
LEFT JOIN brand ON sku.brandid = brand.BRANDID
WHERE  DATE(journey_visits.START_DATE)  BETWEEN '2016-04-01' AND '2016-04-03'
ORDER BY NAME, START_DATE, SKU_NAME

没有限制,您可以按结果集中的所有列进行排序或分组,尽管后者是无用的。

您的查询不会推送任何限制。这里对此进行了很好的解释:请注意,
DATE(旅程访问开始日期)介于'2016-04-01'和'2016-04-03'之间。
不能使用索引,但是旅程访问。开始日期在“2016-04-01 00:00:00”和“2016-04-03 23:59:00”之间可以。