I am writing an SQL query where the query should first search the first value, and only if this value is missing the query should search for the second value.
I have two tables. One of these tables contains the modification date (this is not always filled and can be null) and a creation date which is always filled.
Now what I want is that the query first looks in the table with the modification date and only if it is null looks at the table with the creation date.
Example of the query:
Select *
from all_articles
where to_char(modification_date, 'YYYYMMDD') = to_char(sysdate, 'YYYYMMDD')-1
-- if this is an empty record then
to_char(creation_date, 'YYYYMMDD') = to_char(sysdate, 'YYYYMMDD')-1
Can anyone help me with this query?
Almost all the major RDBMS' available have in built functions to handle such a situation.
The Oracle DB has NVL function which works as follows:
NVL(Modified_dt, Create_dt);
The above will return Modified_dt column data by default. However, if that isn't available, it will return Create_dt.
See here for details:
http://www.w3schools.com/sql/sql_isnull.asp
Related
I have a date column in my table and I would like to 'filter'/select out items after a certain year-month. So if I have data from 2010 on, I have a user input that specifies '2011-10' as the 'earliest date' they want to see data from.
My current SQL looks like this:
select round(sum(amount), 2) as amount,
date_part('month', date) as month
from receipts join items
on receipts.item = items.item
where items.expense = ?
and date_part('year', date)>=2014
and funding = 'General'
group by items.expense, month, items.order
order by items.order desc;
In the second part of the 'where', instead of doing year >= 2014, I want to do something like to_char(date, 'YY-MMMM') >= ? as another parameter and then pass in '2011-10'. However, when I do this:
costsSql = "select round(sum(amount), 2) as amount,
to_char(date, 'YY-MMMM') as year_month
from receipts join items
on receipts.item = items.item
where items.expense = ?
and year_month >= ?
and funding = 'General'
group by items.expense, year_month, items.order
order by items.order desc"
and call that with my two params, I get a postgres error: PG::UndefinedColumn: ERROR: column "year_month" does not exist.
Edit: I converted my YYYY-MM string into a date and passed that in as my param instead and it's working. But I still don't understand why I get the 'column does not exist' error after I created that column in the select clause - can someone explain? Can columns created like that not be used in where clauses?
This error: column "year_month" does not exist happens because year_month is an alias defined the SELECT-list and such aliases can't be refered to in the WHERE clause.
This is based on the fact that the SELECT-list is evaluated after the WHERE clause, see for example: Column alias in where clause? for an explanation from PG developers.
Some databases allow it nonetheless, others don't, and PostgreSQL doesn't. It's one of the many portability hazards between SQL engines.
In the case of the query shown in the question, you don't even need the to_char in the WHERE clause anyway, because as mentioned in the first comment, a direct comparison with a date is simpler and more efficient too.
When a query has a complex expression in the SELECT-list and repeating it in the WHERE clause looks wrong, sometimes it might be refactored to move the expression into a sub-select or a WITH clause at the beginning of the query.
A database column (VARCHAR2 datatype) stores the date/time as 13 digit (milliseconds
) unixtimestamp format. Now when I want to compare the column with a oracle date (in question), The error thrown as 'invalid number'
I tried both ways,
converting the 13digit number to Date and compare with the date in question like below. The expressions seems valid as they are printed in select query, but if i include in the where part, it throws 'invalid number'
Here 'value' is 13th digit unixtimestamp column of VARCHAR2 datatype.
select
TO_DATE('1970-01-01', 'YYYY-MM-DD') + value/86400000,
TO_DATE('2014-04-21', 'YYYY-MM-DD')
from dummytable
-- where and TO_DATE('1970-01-01', 'YYYY-MM-DD') + value/86400000 > TO_DATE('2014-04-21', 'YYYY-MM-DD')
converting the date in question to 13digit unixtimestamp and comparing with the database column.The expressions seems valid as they are printed in select query, but if i include in the where part, it throws 'invalid number'
.
select
value,
(to_date('2013-04-21', 'YYYY-MM-DD') - to_date('1970-01-01', 'YYYY-MM-DD')) * (1000*24*60*60)
from dummytable
-- where value > ((to_date('2013-04-21', 'YYYY-MM-DD') - to_date('1970-01-01', 'YYYY-MM-DD')) * (1000*24*60*60))
any pointers? Thanks in advance.
[EDIT- 1 day later] I see the problem now. There are some data (other rows) for the 'value' column that are non-numeric. But I have another column say field, where always field='date' return value as 13 digit timestamp. Now I think when 'where' condition executes, although the field='date' is in the condition, it is still validating the other values for 'value' which are non-numeric. Is there a way to avoid this ?
Your code works just fine. The problem is in your data. Some of your values is not a number.
create table test
(value varchar2(13));
insert into test(value) values('2154534689000');
--insert into test(value) values('2 54534689000');
select TO_DATE('1970-01-01', 'YYYY-MM-DD') + value/86400000
from test
where TO_DATE('1970-01-01', 'YYYY-MM-DD') + value/86400000 > TO_DATE('2014-04-21', 'YYYY-MM-DD');
This code works fine. But if you uncommented the second insert, you would get exactly the same invalid number error as you get.
UPD. Allan gave you a nice hint, but i feel that it can be good to explain you a bit about views. The fact that you select from a view CAN make a difference. A view is not stored somewhere physically, when you select from it, it is just "added to your query". And then Oracle Query Optimizer starts working. Among other things, it can change the order in which your where predicates are evaluated.
For example, your the view query can have a line where value is not null and it would normally show only 'good' values. But if your query has a predicate where to_date(value,'ddmmyyyy') > sysdate, Oracle can decide to evaluate your predicate earlier, because Oracle predicts that it would "cut off" more rows, thus making the whole query faster and less momery consuming. Of course, execution will crash because of an attempt to convert a null string to date.
I believe, that Allan in his answer that he gave a link to, gave a great way to solve this problem: "wrapping" your query in a subquery that Oracle can't "unwrap":
select value
from
(select value
from my_view
where rownum > 0)
where to_date(value,'ddmmyyyy') > sysdate
Hope that helps.
I have a query that in the select statement uses a custom built function to return one of the values.
The problem I have is every now and then this function will error out because it returns more than one row of information. SQL Error: ORA-01422: exact fetch returns more than requested number of rows
To further compound the issue I have checked the table data within the range that this query should be running and can't find any rows that would duplicate based on the where clause of this Function.
So I would like a quick way to identify on which Row of the original query this crashes so that I can take the values from that query that would be passed into the function and rebuild the Functions query with these values to get it's result and see which two or more rows are returned.
Any ideas? I was hoping there could be a way to force Oracle to process one row at a time until it errors so you can see the results UP to the first error.
Added the code:
FUNCTION EFFPEG
--Returns Effective Pegged Freight given a Effdate, ShipTo, Item
DATE1 IN NUMBER -- Effective Date (JULIANDATE)
, SHAN IN NUMBER -- ShipTo Number (Numeric)
, ITM IN NUMBER -- Short Item Number (Numeric)
, AST IN VARCHAR -- Advance Pricing type (varchar)
, MCU IN VARCHAR Default Null --ShipFrom Plant (varchar)
) RETURN Number
IS
vReturn Number;
BEGIN
Select ADFVTR/10000
into vReturn
from PRODDTA.F4072
where ADEFTJ <= DATE1
and ADEXDJ >= DATE1
and ADAN8 = SHAN and ADITM = ITM
and TRIM(ADAST) = TRIM(AST)
and ADEXDJ = (
Select min(ADEXDJ) ADEXDJ
from PRODDTA.F4072
where ADEFTJ <= DATE1
and ADEXDJ >= DATE1
and ADAN8 = SHAN
and ADITM = ITM
and TRIM(ADAST) = TRIM(AST));
Query that calls this code and passes in the values is:
select GLEXR, ORDTYPE,
EFFPEG(SDADDJ, SDSHAN, SDITM, 'PEGFRTT', SDMCU),
from proddta.F42119
I think the best way to do it is trough Exceptions.
What you need to do is to add the code to handle many rows exception in your function:
EXCEPTION
WHEN TOO_MANY_ROWS THEN
INSERT INTO ERR_TABLE
SELECT your_columns
FROM query_that_sometimes_returns_multiple_rows
In this example the doubled result will go to separated table or you can decide to simply print out with dbms_output.
An easy page to start can be this, then just google exception and you should be able to find all you need.
Hope this can help.
first... sorry for my english.
I have a query like this:
Select *
From tableA
Where (
TO_NUMBER(TO_CHAR(dateA(+),'SYYYY')) = 2013
AND TO_NUMBER(TO_CHAR(dateA(+),'MM')) = 02
AND to_number(to_char(dateA(+),'dd')) <= 25
)
and retrieve me the data from each date until last number that I give as parameter, in this case the day 25. This working but delay very much because the form of "Where" statement... anybody know another way that retrieve the data so fast and with the same functionality?
It sounds like you want
SELECT *
FROM tableA
WHERE dateA BETWEEN trunc( date '2013-02-26', 'MM' ) AND date '2013-02-26'
This will return all the rows where dateA is between the first of the month and the specified date. If there is an index on dateA, Oracle would be able to use it for this sort of query (though whether it actually would is a separate issue).
I have two tables seatinfo(siid,seatno,classid,tsid) and booking (bookid,siid,date,status).
I've input parameter bookDate,v_tsId ,v_clsId. I need exactly one row (bookid) to return. This query is not working. I don't no why. How can I fix it?
select bookid
into v_bookid
from booking
where (to_char(booking.bookdate,'dd-mon-yy'))=(to_char(bookDate,'dd-mon-yy'))
and status=0
and rownum <= 1
and siid in(select siid
from seatinfo
where tsid=v_tsId
and classid= v_clsId);
I also tried this:
select bookid
into v_bookid
from booking,
seatinfo
where booking.siid=seatinfo.siid
and (to_char(booking.bookdate,'dd-mon-yy'))=(to_char(bookDate,'dd-mon-yy'))
and booking.status=0
and rownum <= 1
and seatinfo.tsid=v_tsId
and seatinfo.classid= v_clsId;
Are you saying that you get an "ORA-01422: exact fetch returns more than requested number of rows" when you run both of those queries? That seems highly unlikely since you're including the predicate rownum <= 1. Can you cut and paste from a SQL*Plus session that runs just this query in a PL/SQL block and generates the error?
If you are not complaining about the error you mention in the title, and the problem is just that you're not getting the data you expect, the likely problem is that you apparently have a bookDate parameter that has the same name as a column in your table. That is not going to work. When you say
(to_char(booking.bookdate,'dd-mon-yy'))=(to_char(bookDate,'dd-mon-yy'))
you presumably mean to compare the bookDate column in the booking table against the bookDate parameter. But since column names have precedence over local variables, the left-hand side of your expression is also looking at the bookDate column in the booking table. So you're comparing a column to itself. It would make much more sense to change the name of the parameter (to, say, p_bookDate) and then write
booking.bookDate = p_bookDate
or, if you want to do the comparison ignoring the time component of the dates
trunc( booking.bookDate ) = trunc( p_bookDate )