consider the following example :
CREATETABLE elem (
id INTEGER,
name VARCHAR,
num INTEGER
);
CREATETABLE proxy (
elem_id INTEGER,
time_id INTEGER
);
CREATETABLETIME(
id INTEGER,
TIMESTAMP DATESTAMP
);
INSERTINTO elem VALUES(0,"one",1);
INSERTINTO elem VALUES(1,"one",2);
INSERTINTO elem VALUES(2,"one",3);
INSERTINTO elem VALUES(3,"two",1);
INSERTINTO proxy VALUES(0,0);
INSERTINTO proxy VALUES(0,1);
INSERTINTO proxy VALUES(1,2);
INSERTINTO proxy VALUES(1,3);
INSERTINTO proxy VALUES(2,4);
INSERTINTO proxy VALUES(3,4);
INSERTINTOTIMEVALUES(0,"12/12/2008");
INSERTINTOTIMEVALUES(1,"13/12/2008");
INSERTINTOTIMEVALUES(2,"14/12/2008");
INSERTINTOTIMEVALUES(3,"15/12/2008");
INSERTINTOTIMEVALUES(4,"16/12/2008");
id INTEGER,
name VARCHAR,
num INTEGER
);
CREATETABLE proxy (
elem_id INTEGER,
time_id INTEGER
);
CREATETABLETIME(
id INTEGER,
TIMESTAMP DATESTAMP
);
INSERTINTO elem VALUES(0,"one",1);
INSERTINTO elem VALUES(1,"one",2);
INSERTINTO elem VALUES(2,"one",3);
INSERTINTO elem VALUES(3,"two",1);
INSERTINTO proxy VALUES(0,0);
INSERTINTO proxy VALUES(0,1);
INSERTINTO proxy VALUES(1,2);
INSERTINTO proxy VALUES(1,3);
INSERTINTO proxy VALUES(2,4);
INSERTINTO proxy VALUES(3,4);
INSERTINTOTIMEVALUES(0,"12/12/2008");
INSERTINTOTIMEVALUES(1,"13/12/2008");
INSERTINTOTIMEVALUES(2,"14/12/2008");
INSERTINTOTIMEVALUES(3,"15/12/2008");
INSERTINTOTIMEVALUES(4,"16/12/2008");
What I want is to write a query that will group for each (name,num) the start and end edges of the interval given by the table time:
For example:
one | 1 | 12/12/2008 | 13/12/2008
one | 2 | 14/12/2008 | 15/12/2008
one | 3 | 16/12/2008 | 16/12/2008
two | 1 | 16/12/2008 | 16/12/2008
one | 2 | 14/12/2008 | 15/12/2008
one | 3 | 16/12/2008 | 16/12/2008
two | 1 | 16/12/2008 | 16/12/2008
First we create a simple view to unclutter the query statement.
CREATE temp VIEW all_t ASSELECT elem.name,elem.num,TIME.TIMESTAMPFROM elem,TIME,proxy WHERE proxy.elem_id = elem.id ANDTIME.id = proxy.time_id ;
Then the sql query is pretty straightforward ...
SELECT name,num,MIN(TIMESTAMP),MAX(TIMESTAMP)FROM all_t GROUPBY name, num;
one|1|12/12/2008|13/12/2008
one|2|14/12/2008|15/12/2008
one|3|16/12/2008|16/12/2008
two|1|16/12/2008|16/12/2008
one|1|12/12/2008|13/12/2008
one|2|14/12/2008|15/12/2008
one|3|16/12/2008|16/12/2008
two|1|16/12/2008|16/12/2008
