3,row_number() OVER()对分组后的数据标注行号,从1开始。 postgres=#SELECTrow_number()OVER(PARTITIONBYsubjectORDERBYscoreDESC),*FROMscores; row_number|id|subject|stu_name|score---+---+---+---+---1|2|Chinese|user2|902|3|Chinese|user3|903|1|Chinese|user1|801|8|English|user2|902|7|...
在复杂分析中,可以将ROW_NUMBER()与其他窗口函数如SUM()、AVG()等结合使用。例如,计算每个部门的累计薪资并附加行号: SELECTROW_NUMBER()OVER(PARTITIONBYdepartmentORDERBYsalaryDESC)ASrow_num,department,name,salary,SUM(salary)OVER(PARTITIONBYdepartmentORDERBYsalaryDESC)AScumulative_salaryFROMemployees; 1. 2. ...
1、postgresql 查询每组第一个 ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) 写法:SELECT ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) AS 字段别名 FROM 表名; SELECT * FROM (SELECT *,ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) AS 字段别名(group...
c:770 #8 0x0000000000749bc6 in exec_simple_query (query_string=0x1becfa0 "select row_number() over() as rownum, id from aa;") at postgres.c:1231 #9 0x000000000074aea2 in PostgresMain (argc=<optimized out>, argv=argv@entry=0x1c16f70, dbname=0x1c16e98 "postgres", username=<...
SELECTid,salesperson,region,amount,ROW_NUMBER()OVER(PARTITIONBYregionORDERBYamountDESC)ASrow_numFROMsales; 1. 2. 3. 结果: 3. 获取分组中第一条记录 通过ROW_NUMBER()和WHERE子句,获取每个区域中金额最高的记录: SELECTid,salesperson,region,amountFROM(SELECTid,salesperson,region,amount,ROW_NUMBER()OVER...
解释:row_number():为返回的记录定义各行编号; partition by col1:根据col1进行分组; order by col2:根据col2进行排序。 举例: 原始数据: 原始数据 根据学科分组,按照分数进行排序 select *, row_number() over(partition by course order by score desc) from student; ...
PostgreSQL , rownum , Oracle 兼容性 , row_number 窗口 , limit , PPAS , EDB 背景 Oracle ROWNUM是一个虚拟列,每输出一行递增1。 Oracle rownum 通常被用于LIMIT输出记录数。 SELECT ROWNUM, empno, ename, job FROM emp WHERE ROWNUM < 5 ORDER BY ename; rownum | empno | ename | job ---+---...
SELECTd.department_name"部门名称",concat(e.first_name,',',e.last_name)"姓名",e.salary"月薪",ROW_NUMBER()OVERwAS"row_number",RANK()OVERwAS"rank",DENSE_RANK()wAS"dense_rank",PERCENT_RANK()wAS"percent_rank"FROMemployeeseJOINdepartmentsdON(e.department_id=d.department_id)WHEREd.department_...
rownum在select列表中时重写为row_number() over ()rownum在where子句中时重写为limit... offset... 虚拟列rowid Oracle中的rowid虚拟列返回特定行的具体地址,在PostgreSQL中重写为tableoid || '#' || ctid。 字符串函数 nvl(col, value) Oracle中的nvl(col, value)用来设置默认值,col为空就设置为value;在...
解释： row_number()：为返回的记录定义各行编号；partition by col1 ：根据col1进行分组；order by col2 ：根据col2进行排序。举例：原始数据：根据学科分组，按照分数进行排序 根据分数排序 获取每个科目最低分 select * from (select*,row_number() over(partition by course order by score )...