赞皇建站建设,百度搜索引擎网站,网站开发与维护考试题目,网站开发与发布一、Oracle分析函数入门分析函数是什么#xff1f;分析函数是Oracle专门用于解决复杂报表统计需求的功能强大的函数#xff0c;它可以在数据中进行分组然后计算基于组的某种统计值#xff0c;并且每一组的每一行都可以返回一个统计值。分析函数和聚合函数的不同之处是什么分析函数是Oracle专门用于解决复杂报表统计需求的功能强大的函数它可以在数据中进行分组然后计算基于组的某种统计值并且每一组的每一行都可以返回一个统计值。分析函数和聚合函数的不同之处是什么普通的聚合函数用group by分组每个分组返回一个统计值而分析函数采用partitionby分组并且每组每行都可以返回一个统计值。分析函数的形式分析函数带有一个开窗函数over()包含三个分析子句:分组(partition by), 排序(order by),窗口(rows) 他们的使用形式如下over(partition by xxx order by yyy rows betweenzzz)。注窗口子句在这里我只说rows方式的窗口,range方式和滑动窗口也不提分析函数例子(在scott用户下模拟)示例目的显示各部门员工的工资并附带显示该部分的最高工资。--显示各部门员工的工资并附带显示该部分的最高工资。SELECT E.DEPTNO, E.EMPNO, E.ENAME,E.SAL, LAST_VALUE(E.SAL) OVER(PARTITION BY E.DEPTNO ORDER BY E.SALROWS --unbounded preceding and unbounedfollowing针对当前所有记录的前一条、后一条记录也就是表中的所有记录 --unbounded不受控制的无限的--preceding在...之前 --following在...之后 BETWEEN UNBOUNDED PRECEDINGAND UNBOUNDED FOLLOWING) MAX_SAL FROM EMP E;运行结果示例目的按照deptno分组然后计算每组值的总和SELECT EMPNO, ENAME, DEPTNO, SAL, SUM(SAL) OVER(PARTITION BYDEPTNO ORDER BY ENAME) max_sal FROM SCOTT.EMP;运行结果示例目的对各部门进行分组并附带显示第一行至当前行的汇总SELECT EMPNO, ENAME, DEPTNO, SAL, --注意ROWS BETWEEN unboundedpreceding AND current row 是指第一行至当前行的汇总 SUM(SAL) OVER(PARTITION BYDEPTNO ORDER BY ENAME ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENTROW) max_sal FROM SCOTT.EMP;运行结果示例目标当前行至最后一行的汇总SELECT EMPNO, ENAME, DEPTNO, SAL, --注意ROWS BETWEEN current rowAND unbounded following 指当前行到最后一行的汇总 SUM(SAL) OVER(PARTITION BYDEPTNO ORDER BY ENAME ROWS BETWEEN CURRENT ROW AND UNBOUNDEDFOLLOWING) max_sal FROM SCOTT.EMP;运行结果示例目标当前行的上一行(rownum-1)到当前行的汇总SELECT EMPNO, ENAME, DEPTNO, SAL, --注意ROWS BETWEEN 1 precedingAND current row 是指当前行的上一行(rownum-1)到当前行的汇总 SUM(SAL) OVER(PARTITIONBY DEPTNO ORDER BY ENAME ROWS BETWEEN 1 PRECEDING AND CURRENT ROW)max_sal FROM SCOTT.EMP;运行结果示例目标 当前行的上一行(rownum-1)到当前行的下辆行(rownum2)的汇总SELECT EMPNO, ENAME, DEPTNO, SAL, --注意ROWS BETWEEN 1 precedingAND 1 following 是指当前行的上一行(rownum-1)到当前行的下辆行(rownum2)的汇总 SUM(SAL)OVER(PARTITION BY DEPTNO ORDER BY ENAME ROWS BETWEEN 1 PRECEDINGAND 2 FOLLOWING) max_sal FROM SCOTT.EMP;运行结果一、总体介绍12.1 分析函数如何工作语法 FUNCTION_NAME(,…) OVER ()PARTITION子句 ORDER BY子句 WINDOWING子句 缺省时相当于RANGE UNBOUNDEDPRECEDING1. 值域窗(RANGE WINDOW)RANGE N PRECEDING 仅对数值或日期类型有效,选定窗为排序后当前行之前,某列(即排序列)值大于/小于(当前行该列值–/ N)的所有行,因此与ORDER BY子句有关系。2. 行窗(ROW WINDOW)ROWS N PRECEDING 选定窗为当前行及之前N行。还可以加上BETWEEN AND 形式,例如RANGE BETWEEN m PRECEDING AND nFOLLOWING函数 AVG(eXPr)一组或选定窗中表达式的平均值 CORR(expr, expr) 即COVAR_POP(exp1,exp2) /(STDDEV_POP(expr1) * STDDEV_POP(expr2)),两个表达式的互相关,-1(反相关) ~1(正相关),0表示不相关COUNT() 计数COVAR_POP(expr, expr) 总体协方差COVAR_SAMP(expr, expr) 样本协方差CUME_DIST 累积分布,即行在组中的相对位置,返回0 ~ 1DENSE_RANK 行的相对排序(与ORDER BY搭配),相同的值具有一样的序数(NULL计为相同),并不留空序数FIRST_VALUE 一个组的第一个值LAG(expr,,) 访问之前的行,OFFSET是缺省为1的正数,表示相对行数,DEFAULT是当超出选定窗范围时的返回值(如第一行不存在之前行)LAST_VALUE 一个组的最后一个值LEAD(expr,,) 访问之后的行,OFFSET是缺省为1的正数,表示相对行数,DEFAULT是当超出选定窗范围时的返回值(如最后行不存在之前行)MAX(expr) 最大值MIN(expr) 最小值NTILE(expr) 按表达式的值和行在组中的位置编号,如表达式为4,则组分4份,分别为1 ~4的值,而不能等分则多出的部分在值最小的那组PERCENT_RANK 类似CUME_DIST,1/(行的序数 - 1)RANK 相对序数,答应并列,并空出随后序号RATIO_TO_REPORT(expr) 表达式值 / SUM(表达式值)ROW_NUMBER 排序的组中行的偏移STDDEV(expr) 标准差STDDEV_POP(expr) 总体标准差STDDEV_SAMP(expr) 样本标准差SUM(expr) 合计VAR_POP(expr) 总体方差VAR_SAMP(expr) 样本方差VARIANCE(expr) 方差REGR_ xxxx(expr, expr) 线性回归函数REGR_SLOPE返回斜率等于COVAR_POP(expr1, expr2) / VAR_POP(expr2)REGR_INTERCEPT返回回归线的y截距等于AVG(expr1) - REGR_SLOPE(expr1, expr2) * AVG(expr2)REGR_COUNT返回用于填充回归线的非空数字对的数目REGR_R2返回回归线的决定系数计算式为If VAR_POP(expr2) 0 then return NULLIf VAR_POP(expr1) 0 and VAR_POP(expr2) ! 0 then return 1If VAR_POP(expr1) 0 and VAR_POP(expr2 ! 0thenreturn POWER(CORR(expr1,expr),2)REGR_AVGX计算回归线的自变量(expr2)的平均值去掉了空对(expr1,expr2)后等于AVG(expr2)REGR_AVGY计算回归线的应变量(expr1)的平均值去掉了空对(expr1,expr2)后等于AVG(expr1)REGR_SXX 返回值等于REGR_COUNT(expr1, expr2) * VAR_POP(expr2)REGR_SYY 返回值等于REGR_COUNT(expr1, expr2) * VAR_POP(expr1)REGR_SXY: 返回值等于REGR_COUNT(expr1, expr2) * COVAR_POP(expr1,expr2)首先创建表及接入测试数据create table students(id number(15,0),area varchar2(10),stu_type varchar2(2),score number(20,2));insert into students values(1, 111, g, 80 );insert into students values(1, 111, j, 80 );insert into students values(1, 222, g, 89 );insert into students values(1, 222, g, 68 );insert into students values(2, 111, g, 80 );insert into students values(2, 111, j, 70 );insert into students values(2, 222, g, 60 );insert into students values(2, 222, j, 65 );insert into students values(3, 111, g, 75 );insert into students values(3, 111, j, 58 );insert into students values(3, 222, g, 58 );insert into students values(3, 222, j, 90 );insert into students values(4, 111, g, 89 );insert into students values(4, 111, j, 90 );insert into students values(4, 222, g, 90 );insert into students values(4, 222, j, 89 );commit;二、具体应用1、分组求和1)GROUP BY子句--A、GROUPING SETSselect id,area,stu_type,sum(score) scorefrom studentsgroup by grouping sets((id,area,stu_type),(id,area),id)order by id,area,stu_type;--B、ROLLUPselect id,area,stu_type,sum(score) scorefrom studentsgroup by rollup(id,area,stu_type)order by id,area,stu_type;--C、CUBEselect id,area,stu_type,sum(score) scorefrom studentsgroup by cube(id,area,stu_type)order by id,area,stu_type;--D、GROUPINGselect decode(grouping(id),1,all id,id) id,decode(grouping(area),1,all area,to_char(area)) area,decode(grouping(stu_type),1,all_stu_type,stu_type)stu_type,sum(score) scorefrom studentsgroup by cube(id,area,stu_type)order by id,area,stu_type;二、OVER()函数的使用1、统计名次——DENSE_RANK(),ROW_NUMBER()1)允许并列名次、名次不间断DENSE_RANK()结果如122344456……将score按ID分组排名dense_rank() over(partition by id order by scoredesc)将score不分组排名dense_rank() over(order by score desc)select id,area,score,dense_rank() over(partition by id order by score desc)分组id排序,dense_rank() over(order by score desc) 不分组排序from students order by id,area;2)不允许并列名次、相同值名次不重复ROW_NUMBER()结果如123456……将score按ID分组排名row_number() over(partition by id order by scoredesc)将score不分组排名row_number() over(order by score desc)select id,area,score,row_number() over(partition by id order by score desc)分组id排序,row_number() over(order by score desc) 不分组排序from students order by id,area;3)允许并列名次、复制名次自动空缺rank()结果如12245558……将score按ID分组排名rank() over(partition by id order by scoredesc)将score不分组排名rank() over(order by score desc)select id,area,score,rank() over(partition by id order by score desc) 分组id排序,rank() over(order by score desc) 不分组排序from students order by id,area;4)名次分析cume_dist()——-最大排名/总个数函数cume_dist() over(order by id)select id,area,score,cume_dist() over(order by id) a, --按ID最大排名/总个数cume_dist() over(partition by id order by score desc) b,--ID分组中scroe最大排名值/本组总个数row_number() over (order by id) 记录号from students order by id,area;5)利用cume_dist()允许并列名次、复制名次自动空缺取并列后较大名次结果如22355778……将score按ID分组排名cume_dist() over(partition by id order by scoredesc)*sum(1) over(partition by id)将score不分组排名cume_dist() over(order by score desc)*sum(1)over()select id,area,score,sum(1) over() as 总数,sum(1) over(partition by id) as 分组个数,(cume_dist() over(partition by id order by score desc))*(sum(1)over(partition by id)) 分组id排序,(cume_dist() over(order by score desc))*(sum(1) over())不分组排序from students order by id,area2、分组统计sum(),max(),avg(),RATIO_TO_REPORT()select id,area,sum(1) over() as 总记录数,sum(1) over(partition by id) as 分组记录数,sum(score) over() as 总计 ,sum(score) over(partition by id) as 分组求和,sum(score) over(order by id) as 分组连续求和,sum(score) over(partition by id,area) as 分组ID和area求和,sum(score) over(partition by id order by area) as分组ID并连续按area求和,max(score) over() as 最大值,max(score) over(partition by id) as 分组最大值,max(score) over(order by id) as 分组连续最大值,max(score) over(partition by id,area) as 分组ID和area求最大值,max(score) over(partition by id order by area) as分组ID并连续按area求最大值,avg(score) over() as 所有平均,avg(score) over(partition by id) as 分组平均,avg(score) over(order by id) as 分组连续平均,avg(score) over(partition by id,area) as 分组ID和area平均,avg(score) over(partition by id order by area) as分组ID并连续按area平均,RATIO_TO_REPORT(score) over() as 占所有%,RATIO_TO_REPORT(score) over(partition by id) as 占分组%,score from students;3、LAG(COL,n,default)、LEAD(OL,n,default) --取前后边N条数据取前面记录的值lag(score,n,x) over(order by id)取后面记录的值lead(score,n,x) over(order by id)参数n表示移动N条记录X表示不存在时填充值iD表示排序列select id,lag(score,1,0) over(order by id) lg,score fromstudents;select id,lead(score,1,0) over(order by id) lg,score fromstudents;4、FIRST_VALUE()、LAST_VALUE()取第起始1行值first_value(score,n) over(order by id)取第最后1行值LAST_value(score,n) over(order by id)select id,first_value(score) over(order by id) fv,score fromstudents;select id,last_value(score) over(order by id) fv,score fromstudents;sum(...) over ...【功能】连续求和分析函数【参数】具体参示例【说明】Oracle分析函数NC示例select bdcode,sum(1) over(order by bdcode) aa from bd_bdinfo【示例】1.原表信息 SQL break on deptno skip 1 --为效果更明显把不同部门的数据隔段显示。SQL select deptno,ename,sal2 from emp3 order by deptno;DEPTNO ENAME SAL---------- ---------- ----------10 CLARK 2450KING 5000MILLER 130020 SMITH 800ADAMS 1100FORD 3000SCOTT 3000JONES 297530 ALLEN 1600BLAKE 2850MARTIN 1250JAMES 950TURNER 1500WARD 12502.先来一个简单的注意over(...)条件的不同使用 sum(sal) over (order by ename)... 查询员工的薪水“连续”求和,注意over (order by ename)如果没有order by 子句求和就不是“连续”的放在一起体会一下不同之处SQL select deptno,ename,sal,2 sum(sal) over (order by ename) 连续求和,3 sum(sal) over () 总和, -- 此处sum(sal) over () 等同于sum(sal)4 100*round(sal/sum(sal) over (),4) 份额(%)5 from emp6 /DEPTNO ENAME SAL 连续求和 总和 份额(%)---------- ---------- ---------- ---------- --------------------20 ADAMS 1100 1100 29025 3.7930 ALLEN 1600 2700 29025 5.5130 BLAKE 2850 5550 29025 9.8210 CLARK 2450 8000 29025 8.4420 FORD 3000 11000 29025 10.3430 JAMES 950 11950 29025 3.2720 JONES 2975 14925 29025 10.2510 KING 5000 19925 29025 17.2330 MARTIN 1250 21175 29025 4.3110 MILLER 1300 22475 29025 4.4820 SCOTT 3000 25475 29025 10.3420 SMITH 800 26275 29025 2.7630 TURNER 1500 27775 29025 5.1730 WARD 1250 29025 29025 4.313.使用子分区查出各部门薪水连续的总和。注意按部门分区。注意over(...)条件的不同sum(sal) over (partition by deptno order by ename)按部门“连续”求总和sum(sal) over (partition by deptno) 按部门求总和sum(sal) over (order by deptnoename) 不按部门“连续”求总和sum(sal) over () 不按部门求所有员工总和效果等同于sum(sal)。SQL select deptno,ename,sal,2 sum(sal) over (partition by deptno order by ename)部门连续求和,--各部门的薪水连续求和3 sum(sal) over (partition by deptno) 部门总和, --部门统计的总和同一部门总和不变4 100*round(sal/sum(sal) over (partition by deptno),4)部门份额(%),5 sum(sal) over (order by deptno,ename) 连续求和,--所有部门的薪水连续求和6 sum(sal) over () 总和, -- 此处sum(sal) over ()等同于sum(sal)所有员工的薪水总和7 100*round(sal/sum(sal) over (),4) 总份额(%)8 from emp9 /DEPTNO ENAME SAL 部门连续求和 部门总和 部门份额(%) 连续求和 总和 总份额(%)------ ------ ----- ------------ ---------- --------------------- ------ ----------10 CLARK 2450 2450 8750 28 2450 29025 8.44KING 5000 7450 8750 57.14 7450 29025 17.23MILLER 1300 8750 8750 14.86 8750 29025 4.4820 ADAMS 1100 1100 10875 10.11 9850 29025 3.79FORD 3000 4100 10875 27.59 12850 29025 10.34JONES 2975 7075 10875 27.36 15825 29025 10.25SCOTT 3000 10075 10875 27.59 18825 29025 10.34SMITH 800 10875 10875 7.36 19625 29025 2.7630 ALLEN 1600 1600 9400 17.02 21225 29025 5.51BLAKE 2850 4450 9400 30.32 24075 29025 9.82JAMES 950 5400 9400 10.11 25025 29025 3.27MARTIN 1250 6650 9400 13.3 26275 29025 4.31TURNER 1500 8150 9400 15.96 27775 29025 5.17WARD 1250 9400 9400 13.3 29025 29025 4.314.来一个综合的例子求和规则有按部门分区的有不分区的例子SQL select deptno,ename,sal,sum(sal) over(partition by deptno order by sal) dept_sum,2 sum(sal) over (order by deptno,sal) sum3 from emp;DEPTNO ENAME SAL DEPT_SUM SUM---------- ---------- ---------- ---------- ----------10 MILLER 1300 1300 1300CLARK 2450 3750 3750KING 5000 8750 875020 SMITH 800 800 9550ADAMS 1100 1900 10650JONES 2975 4875 13625SCOTT 3000 10875 19625FORD 3000 10875 1962530 JAMES 950 950 20575WARD 1250 3450 23075MARTIN 1250 3450 23075TURNER 1500 4950 24575ALLEN 1600 6550 26175BLAKE 2850 9400 290255.来一个逆序的即部门从大到小排列部门里各员工的薪水从高到低排列累计和的规则不变。SQL select deptno,ename,sal,2 sum(sal) over (partition by deptno order by deptno desc,saldesc) dept_sum,3 sum(sal) over (order by deptno desc,sal desc) sum4 from emp;DEPTNO ENAME SAL DEPT_SUM SUM---------- ---------- ---------- ---------- ----------30 BLAKE 2850 2850 2850ALLEN 1600 4450 4450TURNER 1500 5950 5950WARD 1250 8450 8450MARTIN 1250 8450 8450JAMES 950 9400 940020 SCOTT 3000 6000 15400FORD 3000 6000 15400JONES 2975 8975 18375ADAMS 1100 10075 19475SMITH 800 10875 2027510 KING 5000 5000 25275CLARK 2450 7450 27725MILLER 1300 8750 290256.体会在... from emp;后面不要加order by 子句使用的分析函数的(partition bydeptno order by sal)里已经有排序的语句了如果再在句尾添加排序子句一致倒罢了不一致结果就令人费劲了。如SQL select deptno,ename,sal,sum(sal) over(partition by deptno order by sal) dept_sum,2 sum(sal) over (order by deptno,sal) sum3 from emp4 order by deptno desc;DEPTNO ENAME SAL DEPT_SUM SUM---------- ---------- ---------- ---------- ----------30 JAMES 950 950 20575WARD 1250 3450 23075MARTIN 1250 3450 23075TURNER 1500 4950 24575ALLEN 1600 6550 26175BLAKE 2850 9400 2902520 SMITH 800 800 9550ADAMS 1100 1900 10650JONES 2975 4875 13625SCOTT 3000 10875 19625FORD 3000 10875 1962510 MILLER 1300 1300 1300CLARK 2450 3750 3750KING 5000 8750 8750RANK()dense_rank()【语法】RANK ( ) OVER ( [query_partition_clause] order_by_clause)dense_RANK ( ) OVER ( [query_partition_clause] order_by_clause)【功能】聚合函数RANK 和 dense_rank 主要的功能是计算一组数值中的排序值。【参数】dense_rank与rank()用法相当【区别】dence_rank在并列关系是相关等级不会跳过。rank则跳过rank()是跳跃排序有两个第二名时接下来就是第四名(同样是在各个分组内)dense_rank()l是连续排序有两个第二名时仍然跟着第三名。【说明】Oracle分析函数【示例】聚合函数RANK 和 dense_rank 主要的功能是计算一组数值中的排序值。在9i版本之前只有分析功能(analytic)即从一个查询结果中计算每一行的排序值是基于order_by_clause子句中的value_exprs指定字段的。其语法为RANK ( ) OVER ( [query_partition_clause] order_by_clause )在9i版本新增加了合计功能(aggregate)即对给定的参数值在设定的排序查询中计算出其排序值。这些参数必须是常数或常值表达式且必须和ORDERBY子句中的字段个数、位置、类型完全一致。其语法为RANK ( expr [, expr]... ) WITHIN GROUP( ORDER BYexpr [ DESCASC ] [NULLS { FIRSTLAST }][, expr [ DESCASC ] [NULLS { FIRSTLAST }]]...)例子1有表Table内容如下COL1 COL21 12 13 23 14 14 25 25 26 2分析功能列出Col2分组后根据Col1排序,并生成数字列。比较实用于在成绩表中查出各科前几名的信息。SELECT a.*,RANK() OVER(PARTITION BY col2 ORDER BY col1) RankFROM table a;结果如下COL1 COL2 Rank1 1 12 1 23 1 34 1 43 2 14 2 25 2 35 2 36 2 5例子2TABLEA (科目分数)数学80语文70数学90数学60数学100语文88语文65语文77现在我想要的结果是(即想要每门科目的前3名的分数)数学100数学90数学80语文88语文77语文70那么语句就这么写select * from (select rank() over(partition by 科目 order by 分数desc) rk,a.* from a) twhere t.rk3;例子3合计功能计算出数值(4,1)在Orade ByCol1,Col2排序下的排序值也就是col14,col21在排序以后的位置SELECT RANK(4,3) WITHIN GROUP (ORDER BY col1,col2) Rank FROMtable;结果如下Rank4dense_rank与rank()用法相当但是有一个区别dence_rank在并列关系是相关等级不会跳过。rank则跳过例如表A B Ca liu wanga jin shua cai kaib yang dub lin yingb yao caib yang 99例如当rank时为select m.a,m.b,m.c,rank() over(partition by a order by b) liufrom test3 mA B C LIUa cai kai 1a jin shu 2a liu wang 3b lin ying 1b yang du 2b yang 99 2b yao cai 4而如果用dense_rank时为select m.a,m.b,m.c,dense_rank() over(partition by a order by b)liu from test3 mA B C LIUa cai kai 1a jin shu 2a liu wang 3b lin ying 1b yang du 2b yang 99 2b yao cai 3 ROW_NUMBER()【语法】ROW_NUMBER() OVER (PARTITION BY COL1 ORDER BY COL2)【功能】表示根据COL1分组在分组内部根据 COL2排序而这个值就表示每组内部排序后的顺序编号(组内连续的唯一的)row_number() 返回的主要是“行”的信息并没有排名【参数】【说明】Oracle分析函数主要功能用于取前几名或者最后几名等【示例】表内容如下nameseqnodescriptionA1testA2testA3testA4testB1testB2testB3testB4testC1testC2testC3testC4test我想有一个sql语句搜索的结果是A1testA2testB1testB2testC1testC2test实现:select name,seqno,descriptionfrom(select name,seqno,description,row_number() over (partitionby name order by seqno) idfrom table_name) where id3;lag()和lead()【语法】lag(EXPR,,)LEAD(EXPR,,)【功能】表示根据COL1分组在分组内部根据 COL2排序而这个值就表示每组内部排序后的顺序编号(组内连续的唯一的)lead () 下一个值 lag() 上一个值【参数】EXPR是从其他行返回的表达式OFFSET是缺省为1 的正数表示相对行数。希望检索的当前行分区的偏移量DEFAULT是在OFFSET表示的数目超出了分组的范围时返回的值。【说明】Oracle分析函数【示例】-- Create tablecreate table LEAD_TABLE(CASEID VARCHAR2(10),STEPID VARCHAR2(10),ACTIONDATE DATE)tablespace COLM_DATApctfree 10initrans 1maxtrans 255storage(initial 64Kminextents 1maxextents unlimited);insert into LEAD_TABLEvalues(Case1,Step1,to_date(20070101,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step2,to_date(20070102,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step3,to_date(20070103,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step4,to_date(20070104,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step5,to_date(20070105,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step4,to_date(20070106,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step6,to_date(20070101,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case1,Step1,to_date(20070201,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case2,Step2,to_date(20070202,yyyy-mm-dd));insert into LEAD_TABLEvalues(Case2,Step3,to_date(20070203,yyyy-mm-dd));commit;结果如下Case1 Step1 2007-1-1 Step2 2007-1-2Case1 Step2 2007-1-2 Step3 2007-1-3 Step1 2007-1-1Case1 Step3 2007-1-3 Step4 2007-1-4 Step2 2007-1-2Case1 Step4 2007-1-4 Step5 2007-1-5 Step3 2007-1-3Case1 Step5 2007-1-5 Step4 2007-1-6 Step4 2007-1-4Case1 Step4 2007-1-6 Step6 2007-1-7 Step5 2007-1-5Case1 Step6 2007-1-7 Step4 2007-1-6Case2 Step1 2007-2-1 Step2 2007-2-2Case2 Step2 2007-2-2 Step3 2007-2-3 Step1 2007-2-1Case2 Step3 2007-2-3 Step2 2007-2-2还可以进一步统计一下两者的相差天数selectcaseid,stepid,actiondate,nextactiondate,nextactiondate-actiondatedatebetween from (select caseid,stepid,actiondate,lead(stepid) over (partition bycaseid order by actiondate) nextstepid,lead(actiondate) over (partition by caseid order by actiondate)nextactiondate,lag(stepid) over (partition by caseid order by actiondate)prestepid,lag(actiondate) over (partition by caseid order by actiondate)preactiondatefrom lead_table)结果如下Case1 Step1 2007-1-1 2007-1-2 1Case1 Step2 2007-1-2 2007-1-3 1Case1 Step3 2007-1-3 2007-1-4 1Case1 Step4 2007-1-4 2007-1-5 1Case1 Step5 2007-1-5 2007-1-6 1Case1 Step4 2007-1-6 2007-1-7 1Case1 Step6 2007-1-7Case2 Step1 2007-2-1 2007-2-2 1Case2 Step2 2007-2-2 2007-2-3 1Case2 Step3 2007-2-3每一条记录都能连接到上/下一行的内容lead () 下一个值 lag() 上一个值select caseid,stepid,actiondate,lead(stepid) over (partition bycaseid order by actiondate) nextstepid,lead(actiondate) over (partition by caseid order by actiondate)nextactiondate,lag(stepid) over (partition by caseid order by actiondate)prestepid,lag(actiondate) over (partition by caseid order by actiondate)preactiondatefrom lead_table
