I'm writing an SQL statment that is supposed to do a count based on a date range. But, for some reason no data is being returned. Before I try and filter the count with my date range, everything works fine. Here is that code.
SELECT
CR.GCR_RFP_ID
,S.RFP_RECEIVED_DT
,CR.GCR_RECEIVED_DT
,CT.GCT_LOB_IND
FROM ADM.GROUP_CHANGE_TASK_FACT CT
JOIN ADM.B_GROUP_CHANGE_REQUEST_DIM CR
ON CR.GROUP_CHANGE_REQUEST_KEY = CT.GROUP_CHANGE_REQUEST_KEY
JOIN ADM.B_RFP_WC_COVERAGE_DIM S
ON S. RFP_ID = CR.GCR_RFP_ID
WHERE CT.GCT_LOB_IND = 'WC'
AND CR.GCR_CHANGE_TYPE_ID IN ('10','20','30','50','60','70','80','90','100','110',
'120','130','140', '150','160','170','180','190','200',
'210','220','230','240','260','270','280','300','310',
'320','330','340','350','360','370','371','372')
AND S.RFP_AUDIT_IND = 'N'
AND S.RFP_TYPE_IND = 'A'
The date field I'm using is called CR.GCR_RECIEVED_DT. This is a new field a in the db and all the records are 01-JAN-00. But I'm still doing the count just to make sure I can grab the data. Now, I added this line:
AND CR.GCR_RECEIVED_DT LIKE '01-JAN-00'
just as a random test thing. I know all the dates are the same. And it works fine, no issues. So I remove that line and replace it with this:
AND CR.GCR_RECEIVED_DT BETWEEN '31-DEC-99' AND '02-JAN-00'
I used this small range to keep it simple. But even though 01-JAN-00 deffinetly falls between those two dates, no data is returned. I have no idea why this is happening. I even tried this line to:
AND CR.GCR_RECEIVED_DT = '01-JAN-00'
and I still don't get data returned. It only seems to work with LIKE. I have checked and the field is a date type. Any help wold be much appreciated.
If your NLS_DATE_FORMAT is set to DD-MON-YY then the apparent discrepancy between the first two results can be explained.
When you use LIKE it implicitly converts the date value on the left-hand side to a string for the comparison, using the default format model, and then compares that to the fixed string; and '01-JAN-00' is like '01-JAN-00'. You're effectively doing:
AND TO_CHAR(CR.GCR_RECEIVED_DT, 'DD-MON-YY') LIKE '01-JAN-00'
Using LIKE to compare dates doesn't really make any sense though. When you use BETWEEN, though, the left-hand side is being left as a date, so you're effectively doing:
AND CR.GCR_RECEIVED_DT BETWEEN TO_DATE('31-DEC-99', 'DD-MON-YY')
AND TO_DATE('02-JAN-00', 'DD-MON-YY')
... and TO_DATE('31-DEC-99', 'DD-MON-YY') is December 31st 2099, not 1999. BETWEEN only works when the first value is lower than the second (from the docs, 'If expr3 < expr2, then the interval is empty'). So you're looking for values bwteen 2099 and 2000, and that will always be empty. If your date model was DD-MON-RR, from the NLS parameter or explicitly via TO_DATE, then it would be looking for values between 1999 and 2000, and would find your records.
Your third result is a little more speculative but suggests that the values in your GCR_RECEIVED_DT field have a time component, or are not in the century you think. This is similar to the LIKE version, except this time the fixed string is being converted to a date, rather than the date being converted to a string; effectively:
AND CR.GCR_RECEIVED_DT = TO_DATE('01-JAN-00', 'DD-MON-YY')
If they were at midnight on 2000-01-01 this would work. Because it doesn't that suggests they are either some time after midnight, or maybe more likely - since you're using a 'magic' date in your existing records - they are another date entirely, quite possibly 1900-01-01.
Here are SQL Fiddles for just past midnight and 1900.
If the field will eventually have a time component for new records you might want to structure the condition like this, and use date literals to be a bit clearer (IMO):
AND CR.GCR_RECEIVED_DT >= DATE '2000-01-01'
AND CR.GCR_RECEIVED_DT < DATE '2000-01-02'
That will find any records at any time on 2000-01-01, and can use an index on that column if one is available. BETWEEN is inclusive, so using BETWEEN DATE '2000-01-01' AND '2000-01-02' would include any records that are exactly at midnight on the later date, which you probably don't want.
Whatever you end up doing, avoid relying on implicit conversions using NLS_DATE_FORMAT as one day it might not be set to what you expect, causing potentially data-corrupting or hard to find bugs; and specify the full four-digit year in the model if you can to avoid ambiguity.
try something like this:
WHERE TRUNC(CR.GCR_RECEIVED_DT) = TO_DATE('01-JAN-00','DD-Mon-YY')
TRUNC without parameter removes hours, minutes and seconds from a DATE.
Related
can anyone explain me the working of trunc(date) function in oracle.
my query is as below.
select trunc(tran_date) from tablename;
i have not passed any format type.
If i compare the date present in table without having trunc(date) it will not give any output.
and if compare date table with trunc(date) it will give me proper ouptut.
please explain how it is working.
and is there any replacement for trunc function as it is taking too much time.
trunc(tran_date) returns the date portion of the date column with no time component (which is midnight at the start of the day).
Despite its name, the date data type in Oracle includes the time. This is even more confusing because you sometimes do not see the time in the result set (depending on how you access the data).
The dates that you are comparing to have no time component. So, the comparison works with trunc(). But the time component on tran_date prevents the comparison from working without trunc().
I am having an odd issue with a select statement in SQL Server Express, hopefully someone can shed some light on why I'm experiencing this behavior as well as the right way to do it.
When I run this query it returns exactly what I would expect:
SELECT
Action, TimeOccurred, UserName, IPv4From, ShareName,
FullFilePath, NewPathName, FromServer
FROM
File_System_Profiles
WHERE
Action LIKE '%create%'
AND (TimeOccurred >= '04/27/2017')
All those entries from 4/27 and anything after that.
When I run this query it returns 0 results which is extremely odd since there are entries for 4/27 in the previous query's results:
SELECT
Action, TimeOccurred, UserName, IPv4From, ShareName,
FullFilePath, NewPathName, FromServer
FROM
File_System_Profiles
WHERE
Action LIKE '%create%'
AND (TimeOccurred = '04/27/2017')
All I removed was the > between the = and the date and I get no results. I can clearly see when I run the first query that there are results where 04/27/2017 is the date that something occurred. If the first query didn't work I would assume there was a problem with my date format of MM/DD/YYYY and what is actually in the column YYYY-MM-DD HH:MM:SS but since the first one works it seems logical that the second one should.
It is a problem of the date format. As you mentioned, you are using Date format as "YYYY-MM-DD HH:MM:SS" so you should know that the value "04/27/2017" will be taken as "04/27/2017 00:00:00" when used in the comparison.
I assume that you have no record where the value in date field is "04/27/2017 00:00:00" and that is why when you use = operator, it does not match any record. However, the operator >= picks the records where hour:minute:second part of the date exist. As an example "04/27/2017 01:10:00" is greater than "04/27/2017 00:00:00" and therefore the > operator fetches those records.
Hope it helps.
First, always use ISO standard formats for comparison. Your code should look more like this:
where Action LIKE '%create%' AND
TimeOccurred = '2017-04-27'
Nauman explained the problem, which is the time component on TimeOccurred. You can solve this in various ways. One method is to convert to date. Something like this:
where Action LIKE '%create%' AND
cast(TimeOccurred as date) = '2017-04-27'
Depending on the database, the cast() might be replaced by trunc() or date_trunc() or something else.
However, I prefer this version:
where Action LIKE '%create%' AND
TimeOccurred >= '2017-04-27' AND
TimeOccurred < '2017-04-28'
It gets to the heart of the problem. And -- better yet -- SQL optimizers can make use of an index.
I understand that querying a date will fail as its comparing a string to date and that can cause an issue.
Oracle 11.2 G
Unicode DB
NLS_DATE_FORMAT DD-MON-RR
select * from table where Q_date='16-Mar-09';
It can be solved by
select * from table where trunc(Q_date) = TO_DATE('16-MAR-09', 'DD-MON-YY');
What I don't get is why this works.
select* from table where Q_date='07-JAN-08';
If anyone can please elaborate or correct my mindset.
Thanks
Oracle does allow date literals, but they depend on the installation (particularly the value of NLS_DATE_FORMAT as explained here). Hence, there is not a universal format for interpreting a single string as a date (unless you use the DATE keyword).
The default format is DD-MM-YY, which seems to be the format for your server. So, your statement:
where Q_date = '07-JAN-08'
is interpreted using this format.
I prefer to use the DATE keyword with the ISO standard YYYY-MM-DD format:
where Q_Date = DATE '2008-01-07'
If this gets no rows returned:
select * from table where Q_date='16-Mar-09';
but this does see data:
select * from table where trunc(Q_date) = TO_DATE('16-MAR-09', 'DD-MON-YY');
then you have rows which have a time other than midnight. At this point in the century DD-MON-RR and DD-MON-YY are equivalent, and both will see 09 as 2009, so the date part is right. But the first will only find rows where the time is midnight, while the second is stripping the time off via the trunc, meaning the dates on both sides are at midnight, and therefore equal.
And since this also finds data:
select* from table where Q_date='07-JAN-08';
... then you have rows at midnight on that date. You might also have rows with other times, so checking the count with the trunc version might be useful.
You can check the times you actually have with:
select to_char(q_date, 'YYYY-MM-DD HH24:MI:SS') from table;
If you do want to make sure you catch all times within the day you can use a range:
select * from table where
q_date >= date '2009-03-16'
and q_date < date '2009-03-17';
Quick SQL Fiddle demo.
Although it sounds like you're expecting all the times to be midnight, which might indicate a data problem.
I am trying to fetch the records which are having all time stamp columns.
I am using the following query to fetch the products that are created between the final date and (final date - 30) days, i.e products created during the last 30 days that fall in the 'final date' range.
I have products that are created on 30-OCT-2014. For the same products, the initiated date is 12-NOV-2014. However they are not being fetched when I using the below query.
SELECT A.ROW_ID,
A.PROD_NAME
FROM PROD A,
PROD_REL B
WHERE A.ROW_ID = B.PAR_ROW_ID
AND TO_DATE(A.CREATED_DT,'YYYY-MM-DD') BETWEEN (TO_DATE(B.FINAL_DATE,'YYYY-MM-DD') - 30)
AND (TO_DATE(B.FINAL_DATE,'YYYY-MM-DD'));
So, could you please let me know if I am missing something?
Here is a link to a SQLFiddle that demonstrates the problem.
… or just fix your format string TO_DATE(A.CREATED,'DD-MON-YYYY')
SQL Fiddle
Storing dates as DATE, is , of course, always a good starting point.
Since your data types are all dates, there is no need to use to_date. It's harmful, in fact, since to_date doesn't take a date as a parameter. Oracle has to do an implicit conversion from a date to a string, using your session's NLS_DATE_FORMAT which gets passed in to to_date and converted back to a date using the explicit format mask you specified. If the two conversions aren't using the same format mask, bad things happen.
Your WHERE clause just needs to be
AND a.created_dt BETWEEN b.final_date - 30
AND b.final_date
If I make that change, your SQLFiddle returns two rows
Problem: I have a large database table (~500k records) which has a list of dates stored in a varchar2(15) column. These dates are stored in varying formats, ie. some are yyyy-mm-dd, some are mm/dd/yyyy, some are dd/mm/yy, some are mm/dd/yy, etc. Ie:
1994-01-13
01/13/1994
01/13/94
13/01/94
13/01/1994
etc
I need to be able to shift these dates slightly, for example to add 30 days to each date. (This is an oversimplification of my objective but it's easier to explain this way).
If all the dates were formatted consistently, I would achieve this as follows:
UPDATE history_table
SET some_date_col =
to_char(to_date(some_date_col, 'mm/dd/yyyy')+30, 'mm/dd/yyyy')
WHERE some_date_col IS NOT NULL;
Due to the size of the database, I cannot afford to loop through the values one by one and parse the date value. Can anyone suggest a means to accomplish this without loops, ie with a mass UPDATE statement?
Are the formats of these dates really that important? They should be datetime columns. Then you could just use date math functions on that field.
well, you've got a real problem here.
07/07/1994 is valid for 'MM/DD/YYYY' and 'DD/MM/YYYY'
However, outside of that issue, you can try nesting decodes.
I entered the following dates into a varchar field:
01/12/2009, 01-12-2009, 2009-01-12, 01/12/09
and using the below, I was consistently returned 1/12/2009. You'll have to figure out all the patterns possible and keep nesting decodes. The other thing you could do is create a function to handle this. Within the function, you can check with a little more detail as to the format of the date. It will also be easier to read. You can use the function in your update statement so that should be faster than looping through, as you mentioned.
(for what its worth, looping through 500k rows like this shouldn't take very long. I regularly have to update row by row tables of 12 million records)
select mydate,
decode(instr(mydate,'-'),5,to_date(mydate,'YYYY-MM-DD'),3,to_date(mydate,'MM-DD-YYYY'),
decode (length(mydate),8,to_date(mydate,'MM/DD/YY'),10,to_date(mydate,'MM/DD/YYYY')))
from mydates;
and here is the update statement:
update mydates set revdate = decode(instr(mydate,'-'),5,to_date(mydate,'YYYY-MM-DD'),3,to_date(mydate,'MM-DD-YYYY'),
decode (length(mydate),8,to_date(mydate,'MM/DD/YY'),10,to_date(mydate,'MM/DD/YYYY')))
IMHO, you have a bigger problem:
If some dates are dd/mm/yyyy and some are mm/dd/yyyy how can you difference which format applies for certain date?
for example, how can I know if a value "12/09/2008" means December or September?