I want to filter out the bookings of Table 1 which is in between the date range of Table 2.
Table 1:
Booking_ID | starts | ends
Table 2:
ID | holiday_starts | holiday_ends
I know there is a overlap function in redshift which can be used but I am not able to figure out how to pass all the date values of table 2 into the overlap function.
I want to do something like
select Booking_ID
from table1
where (table1.starts, table1.ends) overlaps (select holiday_starts, holiday_ends
from table2)
Related
I have a database table with data similar to this.
create table DataTable (
name text,
value number
)
insert into DataTable values
('A', 1),('A', 2),('B', 3),('Other', 5),('C', 1);
And i have another table
create table "group" (
name text,
default boolean
)
insert into "group" values
('A', false),('B', false),('Other', true);
I want to group the data in the first table based on the defined groups in the second table.
Expected output
Name | sum
A | 3
B | 3
Other | 6
Right now I'm using this query:
select coalesce(g.name, (select name from group where default = true)) name
sum(dt.value)
from DataTable dt
left join group g on dt.name = g.name
group by 1
This works but can cause performance tips in some situations. Any better way to do this?
So I am trying to create a database that can store videos from products, but I do intend to add a few million of them. So obviously I want the performance to be as good as possible.
I wanted to achieve the following:
BIGINT | SMALLSERIAL | VARCHAR(30)
product_id | video_id | video_hash
1 1 Dkfjoie124
1 2 POoieqlgkQ
1 3 Xd2t9dakcx
2 1 Df2459Afdw
However, when I insert a new video for a product:
INSERT INTO TABLE (product_id, video_hash) VALUES (2, DSpewirncS)
I want the following to happen:
BIGINT | SMALLSERIAL | VARCHAR(30)
product_id | video_id | video_hash
1 1 Dkfjoie124
1 2 POoieqlgkQ
1 3 Xd2t9dakcx
2 1 Df2459Afdw
2 2 DSpewirncS
Will this happen when I set the column type for video_id to SMALLSERIAL? Because I am afraid that it will insert a different value (the highest in the entire column), which I do not want.
Thanks.
No, a serial is bound to a sequence and that doesn't reset without telling it to do.
But if you want an ordinal for the videos per products you can query the table to produce it using the row_number() window function.
SELECT product_id,
row_number() OVER (PARTITION BY product_id
ORDER BY video_id) video_ordinal,
video_hash
FROM table;
You could also create a view for this query for convenience, so that you can query the view instead of the table and the view would look like you want it.
I would like to know an efficient to way to fetch the data in the following case.
There are two tables say Table1 and Table2 having two common field say contry and pincode and other table "Table3" having key fields of first two tables (DNO, MPNO).
Here is the little glitch, In table3 data, if it is having DNO it wont have MPNO
So when in the selection screen(Pic no2) if the use enter any thing, result should be as follows
**MFID | DNO | MPNO | COUNTRY | PINCODE**
----------
00001 | 10011 | novalue | IN | 4444
00002 | Novalue | 1200 | IN | 5555
00003 | 300 | novalue | US | 9999
( as you can observe if DNO present no MPNO , vice versa )
Please have a look at the pictures for a clear picture :-)
Table Relation:
Selection screen with select options:
The code shouldn't be long.
PSEUDO CODE:
Select queries:
Select * from table3 into it_table3.
Select * from table1 FOR ALL ENTRIES IN it_table3 INTO it_table1
WHERE dno = table3-dno.
Select * from table2 FOR ALL ENTRIES IN it_table3 INTO it_table2
WHERE mpno = table3-mpno.
Loop at internal table 3 and build final table.
LOOP at it_table3 into wa_table3.
IF wa_table3-dno IS NOT INITIAL.
READ it_table1 where dno = wa_table3-dno.
ELSE.
READ it_table2 where mpno = wa_table3-mpno.
ENDIF.
ENDLOOP.
Hope this was the answer you were hoping to find!
Building of efficient select will require information about obligatory fields in your selection screen, as well as about alleged production size of all 3 tables. However, without this information let's assume that table1 and table2 are reference tables and table3 is a transaction table, as onr can assume from their structure. It would be sensible to build selection in a following way:
Selecting data from reference tables. As you said fields DNO/MPNO are mutually exclusive then there will be no hits of country/pincode pair in both reference tables, so JOIN is useless here. However we can merge 2 result sets in single itab without any constraints' violations.
TYPES: BEGIN OF tt_result,
dno TYPE table1-dno,
mpno TYPE table2-mpno,
country TYPE table1-country,
pincode TYPE table1-pincode,
...other field from table3
END OF tt_result.
DATA: itab_result TYPE tt_result.
SELECT dno
FROM table1
INTO CORRESPONDING FIELDS OF TABLE itab_result
WHERE pincode IN so_pincode
AND country IN so_country.
SELECT mpno
FROM table2
APPENDING CORRESPONDING FIELDS OF TABLE itab_result
WHERE pincode IN so_pincode
AND country IN so_country.
FOR ALL ENTRIES addition allows specifying the same table in FOR ALL ENTRIES clause and in INTO clause, so we can fill our result table with absent table3 data by DNO/MPNO key.
SELECT *
FROM table3
INTO CORRESPONDING FIELDS OF TABLE itab_result
FOR ALL ENTRIES IN itab_result
ON itab_result~dno = itab3~dno
AND itab_result_mpno = itab3~mpno.
Struggling with what I thought would be a straightforward operation...
EDIT: SQLFiddle available here: http://sqlfiddle.com/#!15/11711/1/0
Using PostgreSQL 9.4, pretend I have a query that returns this two-column set:
CATEGORY | TOTAL
all | 14
soccer | 5
baseball | 6
hockey | 3
However I'd prefer to pivot it into a single-row set:
ALL | SOCCER | BASEBALL | HOCKEY
14 | 5 | 6 | 3
In other words, I want all my "CATEGORY" values to become columns, with the corresponding "TOTAL" value to be placed in the first row under the appropriate column.
I've been trying to use CROSSTAB()... but as of now I'm getting the following error:
ERROR: a column definition list is required for functions returning "record"
For reference, here's what I'm trying to put as my SQL command:
SELECT * FROM crosstab(
$$
WITH "countTotal" AS (
SELECT text 'all' AS "sportType", COUNT(*) AS "total"
FROM log
WHERE type = 'SPORT_EVENT_CREATED'
GROUP BY "sportType"
),
"countBySportType" AS (
SELECT sport_type AS "sportType", COUNT(*) AS "total"
FROM log
WHERE type = 'SPORT_EVENT_CREATED'
GROUP BY "sportType"
)
SELECT * FROM "countTotal"
UNION
SELECT * FROM "countBySportType"
$$
)
I think you have to specify names and types of the output columns. From the postgres manual tablefunc
The crosstab function is declared to return setof record, so the
actual names and types of the output columns must be defined in the
FROM clause of the calling SELECT statement, for example:
SELECT * FROM crosstab('...') AS ct(row_name text, category_1 text, category_2 text);
You have to use crosstabN(text) to use it with dynamic number of columns. This PostgreSQL Crosstab Query whole lot of details about the cross tab query.
One more post Dynamic alternative to pivot with CASE and GROUP BY
Postgres:
create table stock(item_id int primary key, balance float);
insert into stock values(10,2200);
insert into stock values(20,1900);
select * from stock;
create table buy(item_id int primary key, volume float);
insert into buy values(10,1000);
insert into buy values(30,300);
select * from buy;
results:
item_id | balance
---------+---------
10 | 2200
20 | 1900
(2 rows)
item_id | volume
---------+--------
10 | 1000
30 | 300
(2 rows)
Now i want another table which include these two table's data.
The new table which has 3 rows of data with item_id(10,20,30) and no duplication
I need query for this; either by merge or join.
I'm guessing:
that you really want a view rather than a table
that the values in the 'buy' table are supposed to be deducted from the 'stock'
so here's what I think you are after:
create view v_current_stock as
select item_id, sum(balance) as balance
from ( select item_id, balance from stock
union all
select item_id, -volume from buy )
group by item_id;
EDIT: seems like my guesswork was a bit off (see comments). Perhaps you are looking for a full join:
create view v as
select * from stock full join buy using (item_id);
select * from v;
item_id | balance | volume
---------+---------+--------
10 | 2200 | 1000
20 | 1900 |
30 | | 300
You can use a insert into ... select syntax :
create table mytable(item_id int primary key, balance float, volume float);
insert into mytable
select distinct stock.item_id, balance, volume
from stock
inner join buy on buy.item_id = stock.item_id;
You can use a different type of join if needed (left join or full join). In your case, I think you need a full join, but since I'm not sure I'll stick with the inner join in the example.