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我正在尋找可以在「order by」子句中使用多少個列,例如我有一個列NAME asc,START_DATE asc,SKU_GROUP asc,並希望在order子句中添加SKU_NAME asc。我目前正在使用1組,但爲了好奇,MySQL中可以使用多少個?mysql中允許多少個按列排序,類似group by?
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
你的查詢不會推動任何限制。 –
這在這裏解釋得很好:https://dev.mysql.com/doc/mysql-reslimits-excerpt/5.5/en/column-count-limit.html – mitkosoft
請注意'DATE(journey_visits.START_DATE)BETWEEN'2016- 04-01'和'2016-04-03''不能使用索引,但是'journey_visits.START_DATE BETWEEN'2016-04-01 00:00:00'和'2016-04-03 23:59:00''能夠。 – Strawberry