Oracle 11gR2 中引入了 LISTAGG 函数,以简化字符串聚合。在Oracle 12cR2中,它已扩展为包括溢出错误处理。Oracle 19c 中通过包含 DISTINCT 关键字,可以从 LISTAGG 结果中删除重复项。
owner='COLLEGE' --查询当前用户连接 select count(*) from v$session --查看当前用户权限 select * from session_privs; --添加主键 alter table test add constraint pk_test primary key (userid); --删除主键 alter table 表名 drop constraint 主键名 --查看当前数据库所有用户 select * from dba_users...
count(*) over(partition by deptno order by empno) from emp;--按照deptno分组并累计计数 注意加order by和不加order by 的区别: 加了order by统计的是第一行到当前行的总数, 但是不加order by统计的是整个数据的总数 select empno,ename,mgr,sal,deptno,count(EMPNO) over(partition by deptno) from emp...
例如: COUNT(*), MIN(字段名), MAX(字段名), AVG(字段名), DISTINCT(字段名), TO_CHAR(DATE字段名,'YYYY-MM-DD HH24:MI:SS') NVL(EXPR1, EXPR2)函数 解释: IF EXPR1=NULL RETURN EXPR2 ELSE RETURN EXPR1 DECODE(AA﹐V1﹐R1﹐V2﹐R2...)函数 解释: IF AA=V1 THEN RETURN R1 IF AA=V2...
小提示:count(distinct表达式),遇到重复数据,只记录一次 分析函数:Oracle从8.1.6版本开始提供分析函数。分析函数是对一组查询结果进行运算,然后获行结果。与聚合函数的区别在于返回多行,聚合函数每组返回一行。用于对分组后组内进行排序。 语法: 函数名([参数]) over ([分区子句][排序子句]);--分区子句(partition...
v_tabname from dual; stmt := 'select count(*) from "' || v_owner || '"."' || v_tabname || '"'; EXECUTE IMMEDIATE stmt INTO num_rows; EXECUTE IMMEDIATE 'insert into table_count values('''||v_owner||''','''||v_tabname||''','''||to_number(num_rows)||''')'; ...
Depth of the index from its root block to its leaf blocks (BLEVEL) Number of leaf blocks (LEAF_BLOCKS) Number of distinct index values (DISTINCT_KEYS) Average number of leaf blocks for each index value (AVG_LEAF_BLOCKS_PER_KEY)
Returns: the result of the aggregation process ensureSet protected Set<E> ensureSet() Return a set that can be used to store distinct values, creating it if one has not already been created. Returns: a set that can be used to store distinct valuesSkip...
count(distinct Val) over(partition by PID) 列値が何通りあるかを調べる distinctオプションを指定した分析関数のcount関数は、列値が何通りあるかを調べる時などに使われます。 Copy Copied to Clipboard Error: Could not Copy create table CntDisSample(ID,Val) as select 111,1 from dual union...
create or replace function f_count(c_name in varchar2) return number as resultCount number; begin select count(distinct s.Sno) into resultCount from student s,course c,sc sc where s.Sno=sc.Sno and c.Cno=sc.Cno and c.Cname=c_name; return(resultCount); end f_count; / 调用...