My table has the below sample data:
DECLARE #FHTable table (PK_ID int,FK_ID int,P_ID int, T_ID int, A_day int,A_hour TIME,D_day int,D_hour time)
INSERT INTO #FHtable VALUES (129,194,252,1005322,NULL,NULL,1,'02:30:00.0000000')
INSERT INTO #FHtable VALUES (130,194,311,1000891,3,'04:30:00.0000000',null,null)
INSERT INTO #FHtable VALUES (131,194,311,1000129,NULL,NULL,4,'03:30:00.0000000')
INSERT INTO #FHtable VALUES (132,194,252,1000025,6,'03:00:00.0000000',null,null)
SELECT * FROM #FHtable
My final result Should be of the below table:
DECLARE #FinalResultTable TABLE (FK_ID int,P_IDFrom int,P_IDTO INT, T_IDFrom int,T_IDTo INT, A_day int,A_hour TIME,D_day int,D_hour time)
INSERT INTO #FinalResultTable VALUES (194,252,311,1005322,1000891,3,'04:30:00.0000000',1,'02:30:00.0000000')
INSERT INTO #FinalResultTable VALUES (194,311,252,1000129,1000025,6,'03:00:00.0000000',4,'03:30:00.0000000')
select * from #FinalResultTable
The logic is there will be 4 rows for each FK_ID. The first and the second row is a source to destination and the 3rd and 4th row is again a source to destination.
Can you please help
As I pointed out in the comments, it's not very clear what is the logic that joins each arrival with the corresponding departure.
What it's clear to me it's that your title is wrong: you are not talking about converting rows to columns. Instead, you are just grouping 2 by 2 the rows of the table. So, you have 2 approaches, using a GROUP BY or just using a JOIN, it depends on what is exactly your logic.
Here is an example:
select A.FK_ID,
A.PK_ID as P_IDFrom, B.PK_ID as P_IDTO,
A.T_ID as T_IDFrom int, B.T_ID as T_IDTo,
B.A_day, B.A_hour,
A.D_day, A.D_hour
from #FHTable A
join #FHTable B on B.PK_ID+1=A.PK_ID
where A.A_day is null
(this assumes that an arrivals's PK is always +1 w.r.t. its departure).
Related
I have a table cusers with a primary key:
primary key(uid, lid, cnt)
And I try to insert some values into the table:
insert into cusers (uid, lid, cnt, dyn, ts)
values
(A, B, C, (
select C - cnt
from cusers
where uid = A and lid = B
order by ts desc
limit 1
), now())
on conflict do nothing
Quite often (with the possibility of 98%) a row cannot be inserted to cusers because it violates the primary key constraint, so hard select queries do not need to be executed at all. But as I can see PostgreSQL first counts the select query as a result of dyn column and only then rejects row because of uid, lid, cnt violation.
What is the best way to insert rows quickly in such situation?
Another explanation
I have a system where one row depends on another. Here is an example:
(x, x, 2, 2, <timestamp>)
(x, x, 5, 3, <timestamp>)
Two columns contain an absolute value (2 and 5) and relative value (2, 5 - 2). Each time I insert new row it should:
avoid same rows (see primary key constraint)
if new row differs, it should count a difference and put it into the dyn column (so I take the last inserted row for the user according to the timestamp and subtract values).
Another solution I've found is to use returning uid, lid, ts for inserts and get user ids which were really inserted - this is how I know they have differences from existing rows. Then I update inserted values:
update cusers
set dyn = (
select max(cnt) - min(cnt)
from (
select cnt
from cusers
where uid = A and lid = B
order by ts desc
limit 2) Table
)
where uid = A and lid = B and ts = TS
But it is not a fast approach either, as it seeks all over the ts column to find the two last inserted rows for each user. I need a fast insert query as I insert millions of rows at a time (but I do not write duplicates).
What the solution can be? May be I need a new index for this? Thanks in advance.
It's all in the title. Documentation has something like this:
SELECT *
FROM crosstab('...') AS ct(row_name text, category_1 text, category_2 text);
I have two tables, lab_tests and lab_tests_results. All of the lab_tests_results rows are tied to the primary key id integer in the lab_tests table. I'm trying to make a pivot table where the lab tests (identified by an integer) are row headers and the respective results are in the table. I can't get around a syntax error at or around the integer.
Is this possible with the current set up? Am I missing something in the documentation? Or do I need to perform an inner join of sorts to make the categories strings? Or modify the lab_tests_results table to use a text identifier for the lab tests?
Thanks for the help, all. Much appreciated.
Edit: Got it figured out with the help of Dmitry. He had the data layout figured out, but I was unclear on what kind of output I needed. I was trying to get the pivot table to be based on batch_id numbers in the lab_tests_results table. Had to hammer out the base query and casting data types.
SELECT *
FROM crosstab('SELECT lab_tests_results.batch_id, lab_tests.test_name, lab_tests_results.test_result::FLOAT
FROM lab_tests_results, lab_tests
WHERE lab_tests.id=lab_tests_results.lab_test AND (lab_tests.test_name LIKE ''Test Name 1'' OR lab_tests.test_name LIKE ''Test Name 2'')
ORDER BY 1,2'
) AS final_result(batch_id VARCHAR, test_name_1 FLOAT, test_name_2 FLOAT);
This provides a pivot table from the lab_tests_results table like below:
batch_id |test_name_1 |test_name_2
---------------------------------------
batch1 | result1 | <null>
batch2 | result2 | result3
If I understand correctly your tables look something like this:
CREATE TABLE lab_tests (
id INTEGER PRIMARY KEY,
name VARCHAR(500)
);
CREATE TABLE lab_tests_results (
id INTEGER PRIMARY KEY,
lab_tests_id INTEGER REFERENCES lab_tests (id),
result TEXT
);
And your data looks something like this:
INSERT INTO lab_tests (id, name)
VALUES (1, 'test1'),
(2, 'test2');
INSERT INTO lab_tests_results (id, lab_tests_id, result)
VALUES (1,1,'result1'),
(2,1,'result2'),
(3,2,'result3'),
(4,2,'result4'),
(5,2,'result5');
First of all crosstab is part of tablefunc, you need to enable it:
CREATE EXTENSION tablefunc;
You need to run it one per database as per this answer.
The final query will look like this:
SELECT *
FROM crosstab(
'SELECT lt.name::TEXT, lt.id, ltr.result
FROM lab_tests AS lt
JOIN lab_tests_results ltr ON ltr.lab_tests_id = lt.id'
) AS ct(test_name text, result_1 text, result_2 text, result_3 text);
Explanation:
The crosstab() function takes a text of a query which should return 3 columns; (1) a column for name of a group, (2) a column for grouping, (3) the value. The wrapping query just selects all the values those crosstab() returns and defines the list of columns after (the part after AS). First is the category name (test_name) and then the values (result_1, result_2). In my query I'll get up to 3 results. If I have more then 3 results then I won't see them, If I have less then 3 results I'll get nulls.
The result for this query is:
test_name |result_1 |result_2 |result_3
---------------------------------------
test1 |result1 |result2 |<null>
test2 |result3 |result4 |result5
I need to create a table using postgres that multiplies a row by the difference of the numbers in 2 columns, and provides the corresponding sequence. It's hard to explain, I'll leave a picture to save us a thousand words:
I have found a partial answer to this question in SQL, but it only multiplies by one column, and I'm having trouble with using it in Posgresql:
How to multiply a single row with a number from column in sql.
You can use the generate_series function: https://www.postgresql.org/docs/current/static/functions-srf.html
create table table_a(
a integer primary key,
start_a integer,
end_a integer
);
insert into table_a values
(1, 1, 3),
(2, 2, 5);
create table table_b as
select a, start_a, end_a, g as start_b, g+1 as end_b
from table_a, lateral generate_series(start_a, end_a-1) g;
select * from table_b;
You can try it here: http://rextester.com/RTZWK4070
When using a Table Value Constructor (http://msdn.microsoft.com/en-us/library/dd776382(v=sql.100).aspx) to insert multiple rows, is the order of any identity column populated guaranteed to match the rows in the TVC?
E.g.
CREATE TABLE A (a int identity(1, 1), b int)
INSERT INTO A(b) VALUES (1), (2)
Are the values of a guaranteed by the engine to be assigned in the same order as b, i.e. in this case so they match a=1, b=1 and a=2, b=2.
Piggybacking on my comment above, and knowing that the behavior of an insert / select+order by will guarantee generation of identity order (#4: from this blog)
You can use the table value constructor in the following fashion to accomplish your goal (not sure if this satisfies your other constraints) assuming you wanted your identity generation to be based on category id.
insert into thetable(CategoryId, CategoryName)
select *
from
(values
(101, 'Bikes'),
(103, 'Clothes'),
(102, 'Accessories')
) AS Category(CategoryID, CategoryName)
order by CategoryId
It depends as long as your inserting the records in one shot . For example after inserting if you delete the record where a=2 and then again re insert the value b=2 ,then identity column's value will be the max(a)+1
To demonstrate
DECLARE #Sample TABLE
(a int identity(1, 1), b int)
Insert into #Sample values (1),(2)
a b
1 1
2 2
Delete from #Sample where a=2
Insert into #Sample values (2)
Select * from #Sample
a b
1 1
3 2
I have create a table using create table and with these column:
create table myschema.mytable(
id serial PRIMARY KEY,
row_num integer,
col_num integer,
pix_centroid geometry,
pix_val double precision
)
When I am trying to populate it:
insert into pixelbased (id, row_num, col_num, pix_centroid, pix_val)
values (
DEFAULT,
(select((ST_PixelAsPolygons(rast, 1)).x) from mytable where rid=3),
(select((ST_PixelAsPolygons(rast, 1)).x) from mytable where rid=3),
(select(ST_Centroid((ST_PixelAsPolygons(rast, 1)).geom)) from rwanda8 where rid=3),
(select(ST_PixelAsPolygons(rast, 1)).val from mytable where rid=3)
)
I am encountered with the following error:
ERROR: more than one row returned by a subquery used as an expression.
I know that since I have more than one row for every column it does make sense to have such an error. But I really need to have all the columns calculated as mentioned. Anyone knows what should I do?
In fact I want to insert the result the following query in the table:
select
(ST_PixelAsPolygons(rast, 1)).val as geomval1,
(ST_PixelAsPolygons(rast, 1)).x as X,
(ST_PixelAsPolygons(rast, 1)).y as Y,
(ST_Centroid((ST_PixelAsPolygons(rast, 1)).geom)) as geom
from rwanda8
where rid=3
Anyone knows what should I do?
Just use the select query in instead of the values
insert into pixelbased (row_num, col_num, pix_centroid, pix_val)
select
(ST_PixelAsPolygons(rast, 1)).val as geomval1,
(ST_PixelAsPolygons(rast, 1)).x as X,
(ST_PixelAsPolygons(rast, 1)).y as Y,
(ST_Centroid((ST_PixelAsPolygons(rast, 1)).geom)) as geom
from rwanda8 where rid=3
Do not insert the id as it is a serial and will generate itself.
One of your subqueries returns more than 1 row. So use LIMIT 0,1 or something to get only one single value per subquery.
If you need more than 1 value per column, you should review your insert algorithm and use a cursor for instance.