我们有一个表格，列出“服务时间”的开始和结束日期。我想要一个查询，可以搜索所有行，并根据日期中的间隙识别服务中断。
Data:
Start End
1/1/2000 2/1/2001
2/2/2001 4/1/2001
4/1/2004 6/2/2006
6/3/2006 9/1/2010
8/1/2011 9/1/2012
Desired result:
1/1/2001 - 4/1/2001 //The first two ranges collapsed because no break in service
4/1/2004 - 9/1/2010 // The 3rd and 4th rows collapsed because no real break in service
8/1/2011 - 9/1/2012
这可能更容易在app逻辑或存储过程中完成，只是想知道是否有任何SQL voodoo可以让我接近。
Table definition:
CREATE TABLE CONG_MEMBER_TERM
(
CONG_MEMBER_TERM_ID NUMBER(10, 0) NOT NULL
, CONGRESS_ID NUMBER(10, 0) NOT NULL
, CHAMBER_CD VARCHAR2(30 BYTE) NOT NULL
, CONG_MEMBER_ID NUMBER(10, 0) NOT NULL
, STATE_CD CHAR(2 BYTE) NOT NULL
, CONG_MEMBER_TYPE_CD VARCHAR2(30 BYTE) NOT NULL
, DISTRICT NUMBER(10, 0)
, START_DT TIMESTAMP(6) WITH TIME ZONE
, END_DT TIMESTAMP(6) WITH TIME ZONE
, CREATE_DT TIMESTAMP(6) WITH TIME ZONE NOT NULL
, UPDATE_DT TIMESTAMP(6) WITH TIME ZONE NOT NULL
)
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2945,104,'H',494,'OK','REP',2,to_timestamp_tz('04-JAN-95 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('04-OCT-96 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.47.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.48.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2946,105,'H',494,'OK','REP',2,to_timestamp_tz('07-JAN-97 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('19-DEC-98 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.47.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2947,106,'H',494,'OK','REP',2,to_timestamp_tz('06-JAN-99 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('15-DEC-00 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.47.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2948,109,'S',494,'OK','SEN',null,to_timestamp_tz('04-JAN-05 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('09-DEC-06 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.48.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2949,110,'S',494,'OK','SEN',null,to_timestamp_tz('04-JAN-07 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-JAN-09 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.48.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2951,111,'S',494,'OK','SEN',null,to_timestamp_tz('06-JAN-09 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('22-DEC-10 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.48.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
Insert into CONG_MEMBER_TERM (CONG_MEMBER_TERM_ID,CONGRESS_ID,CHAMBER_CD,CONG_MEMBER_ID,STATE_CD,CONG_MEMBER_TYPE_CD,DISTRICT,START_DT,END_DT,CREATE_DT,UPDATE_DT) values (2950,112,'S',494,'OK','SEN',null,to_timestamp_tz('05-JAN-11 01.00.00.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),null,to_timestamp_tz('02-MAY-12 09.45.48.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'),to_timestamp_tz('02-MAY-12 09.45.49.000000000 AM -05:00','DD-MON-RR HH.MI.SS.FF AM TZR'));
如果之前的服务与下一次服务之间的差距大于24个月，那么它将被视为服务中的“差距”。
_mike
答案 0 :(得分：3)
这是使用带有示例的分析函数在SQL中折叠时间范围的标准方法。
你的桌子：
SQL> create table mytable (startdate,enddate)
2 as
3 select date '2000-01-01', date '2001-02-01' from dual union all
4 select date '2001-02-02', date '2001-04-01' from dual union all
5 select date '2004-04-01', date '2006-06-02' from dual union all
6 select date '2006-06-03', date '2010-09-01' from dual union all
7 select date '2011-08-01', date '2012-09-01' from dual
8 /
Table created.
查询：
SQL> select min(startdate) startdate
2 , max(enddate) enddate
3 from ( select startdate
4 , enddate
5 , max(rn) over (order by startdate) maxrn
6 from ( select startdate
7 , enddate
8 , case lag(enddate) over (order by startdate)
9 when startdate-1 then
10 null
11 else
12 rownum
13 end rn
14 from mytable
15 )
16 )
17 group by maxrn
18 order by startdate
19 /
STARTDATE ENDDATE
------------------- -------------------
01-01-2000 00:00:00 01-04-2001 00:00:00
01-04-2004 00:00:00 01-09-2010 00:00:00
01-08-2011 00:00:00 01-09-2012 00:00:00
3 rows selected.
它分三个阶段运作：
这个查询的真正之处在于只需要一个TABLE ACCESS FULL：
SQL> select * from table(dbms_xplan.display_cursor(null,null,'allstats last'))
2 /
PLAN_TABLE_OUTPUT
-------------------------------------------------------------------------------------------------------------------------
SQL_ID 8v1suw8j53tqz, child number 0
-------------------------------------
select min(startdate) startdate , max(enddate) enddate from ( select startdate , enddate
, max(rn) over (order by startdate) maxrn from ( select startdate
, enddate , case lag(enddate) over (order by startdate) when
startdate-1 then null else rownum
end rn from mytable ) ) group by maxrn
order by startdate
Plan hash value: 2933657513
-------------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem |
-------------------------------------------------------------------------------------------------------------------------
| 1 | SORT ORDER BY | | 1 | 5 | 3 |00:00:00.01 | 3 | 2048 | 2048 | 2048 (0)|
| 2 | HASH GROUP BY | | 1 | 5 | 3 |00:00:00.01 | 3 | | | |
| 3 | VIEW | | 1 | 5 | 5 |00:00:00.01 | 3 | | | |
| 4 | WINDOW BUFFER | | 1 | 5 | 5 |00:00:00.01 | 3 | 2048 | 2048 | 2048 (0)|
| 5 | VIEW | | 1 | 5 | 5 |00:00:00.01 | 3 | | | |
| 6 | WINDOW SORT | | 1 | 5 | 5 |00:00:00.01 | 3 | 2048 | 2048 | 2048 (0)|
| 7 | COUNT | | 1 | | 5 |00:00:00.01 | 3 | | | |
| 8 | TABLE ACCESS FULL| MYTABLE | 1 | 5 | 5 |00:00:00.01 | 3 | | | |
-------------------------------------------------------------------------------------------------------------------------
24 rows selected.
的问候，
罗布。
答案 1 :(得分：1)
这可以使用分析来完成，但我不确定您想要从查询中获得什么。
例如：
drop table mydates;
create table mydates (sdate date, edate date);
insert into mydates values (to_date('2000-01-01' ,'YYYY-MM-DD'), to_date('2000-01-02' ,'YYYY-MM-DD'));
insert into mydates values (to_date('2000-01-02' ,'YYYY-MM-DD'), to_date('2000-02-01' ,'YYYY-MM-DD'));
-- insert a gap
insert into mydates values (to_date('2001-01-01' ,'YYYY-MM-DD'), to_date('2001-01-02' ,'YYYY-MM-DD'));
insert into mydates values (to_date('2001-01-02' ,'YYYY-MM-DD'), to_date('2001-02-01' ,'YYYY-MM-DD'));
这里我们有两组两行，它们之间有服务中断。您可以使用滞后函数轻松地找到start_date与前一行end_date不同的所有行。此SQL将为您提供每个组的起始行：
select *
from
(
select lag(edate, 1, null) over (order by sdate asc) as previous_end,
sdate sd,
edate ed
from mydates
)
where previous_end != sd or previous_end is null;
但我不确定这是你想要的。您可以获得更好的功能并将所有行向下折叠，这样您就可以在每个连续组中获得一行。
如果您发布更完整的示例（包括用于创建对象和数据的脚本），这可能很有用。
select min(sd) sd, max(ed) ed
from
(
select max(grp) over (order by sd) grp,
sd, ed
from
(
select
case
when previous_end != sd or previous_end is null then
rn
else
null
end grp,
sd,
ed
from
(
select lag(edate, 1, null) over (order by sdate asc) as previous_end,
row_number() over (order by sdate asc) as rn,
sdate sd,
edate ed
from mydates
order by sdate asc
)
)
) group by grp
order by sd asc;