sql常用語(yǔ)句舉例-展示頁(yè)
2025-08-02 08:04本頁(yè)面
【正文】 desc結(jié)果：Store_namesalesdateLos Angeles$1500Jan051999Boston$700Jan081999Los Angeles$300Jan081999San Diego$250Jan0719997. 函數(shù)：AVG（平均值）、COUNT（計(jì)數(shù)）、MAX（最大值）、MIN（最小值）、SUM(求和)語(yǔ)句：select 函數(shù)名(字段名) from 表名例：求出sales的總和Select sum(sales) from Store_informationSum(sales)$2750結(jié)果：8. COUNT（計(jì)數(shù)）例：找出Store_information表中 有幾個(gè)store_name 值不是空的記錄Select count(store_name) from Store_informationWhere store_name is not nullcount(store_name)4結(jié)果：補(bǔ)充說明：count和distinct經(jīng)常合起來使用的目的是找出表中有多少個(gè)不重復(fù)的記錄例：找出表中有多少個(gè)不重復(fù)的store_nameSelect count(distinct store_name) from Store_informationcount(store_name)3結(jié)果：9. Group by: 全組排列例：算出每一個(gè)store_name對(duì)應(yīng)的營(yíng)業(yè)額Select store_name,sum(sales) from Store_information group by store_name結(jié)果：store_namesum(sales)Los Angeles$1800Boston$250San Diego$70010. HAVING:一般與grou
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