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SQL

SQL. Aggregation. SQL : Aggregation. “Aggregation” functions o ver values in multiple rows: m in , max , sum , avg , count. Select A 1 , A 2 ,…, A n From R 1 , R 2 , …, R m Where condition. SQL : Aggregation. Select A 1 , A 2 ,…, A n From R 1 , R 2 , …, R m

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SQL

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  1. SQL Aggregation

  2. SQL: Aggregation “Aggregation” functions over values in multiple rows: min, max, sum, avg, count Select A1,A2,…,An From R1,R2, …,Rm Where condition

  3. SQL: Aggregation Select A1,A2,…,An From R1,R2, …,Rm Where condition Group By columns Having condition “Aggregation” functions over values in multiple rows: min, max, sum, avg, count New clauses Demo: simple college admissions database College(cName,state,enrollment) Student(sID,sName,GPA,sizeHS) Apply(sID,cName,major,decision)

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