I have a field that I would like to get the max value of but it is a varchar2(6) field, all numerals. I am unable to change the type of field
The field is a date listed like this 201307 for July 2013. Just using MAX does not work.
Using oracle.
SELECT MAX(date) "MostRecent" FROM tablename;
Should work. YYYYMM is going to sort as newest first in a MAX aggregate or analytic function in Oracle.
Related
I have a column name 'Cos_Date' with value like 14APR2017:00:00:00.
However, for a new column name 'Arrival_Date', I would like to keep the date information but omit time, and keep the data type as Date but not Character. Ex, 14APR2017.
I have tried:
select TO_CHAR(Cos_Date, 'DD-MON-YYYY') ARRIVAL_DATE
But it will delete time information, but data type turns to Character.
I search on this site, and tried both:
select TO_DATE(TO_CHAR(Cos_Date, 'DD-MON-YYYY'), 'DD-MON-YYYY') ARRIVAL_DATE
and:
select TRUNC(Cos_Date) ARRIVAL_DATE
But it will not omit time information.
Can I try something else?
Thank you!
You can't "omit" the time portion of a DATE column in Oracle. The DATE data type always contains a time component. If you don't want to see the time, don't display it, e.g.,
SELECT TO_CHAR(TRUNC(Cos_Date),'DD-MON-YYYY') FROM dual;
In Oracle there is no date data type that has only a year-month-day component.
The DATE data type is stored internally as 7- or 8-bytes which always has year (2-bytes), month (1-byte), day (1-byte), hour (1-byte), minute (1-byte) and second (1-byte).
The TIMESTAMP data type also has fractional seconds (and can also have a time zone).
Can I try something else?
No, you either use a VARCHAR2 string or use a DATE or TIMESTAMP and accept that it has a time component.
Selecting date values without time:
SELECT date_col
FROM table
WHERE TO_CHAR (date_col, 'HH24:MI:SS') = '00:00:00';
1) Why is that this doesn't works
select * from table where trunc(field1)=to_date('25-AUG-15','DD-MON-YY');
select * from table where trunc(field1)=to_date('25/Aug/15','DD/MON/YY');
row is returned in above cases.
So, does this mean that no matter what format the date is there in field1, if it is the valid date and matches with 25th August, it will be returned ( it won't care what format specifier we specify at the right side of the query i.e. DD-MON-YY or DD/MON/YY or anything else) ?
2) but comparsion as string exactly works:
select * from table where to_char(field1)=to_char(to_date
('25/AUG/15','DD/MON/YY'), 'DD/MON/YY');
no row is returned as the comparison is performed exactly.
I have field1 as '25-AUG-15' ( although it can be viewed differently doing alter session NLS_DATE_FORMAT...)
field1 is of DATE type
Any help in understanding this is appreciated specifically with respect to point 1
The DATE data type does not have format -- it's simply a number. So, a DATE 25-Aug-2015 is the same as DATE 25/AUG/15, as well as DATE 2015-08-15, because it's the same DATE.
Strings, on the other hand, are collections of characters, so '25-Aug-2015' is obviously different from '25/AUG/15'.
In the first example you are comparing DATE values. In the second example you are comparing strings.
So you have a field of type DATE with value of The 25th of August 2015,
but it could be visualized in different ways, what in fact is named format.
The DATE has format!
The DATE has implicit format defined by Oracle, in your case it is DD-MON-YY, because you see your field as 25-AUG-15.
You can select your data without TO_DATE conversion, just matching this default format like this:
select * from table where trunc(field1)='25-AUG-15';
In fact, it's not recommended, because if someone will change the default format, Oracle will not be able to understand that you are going to tell him a DATE.
So the to_date conversion in this case:
select * from table where
trunc(field1)=to_date('25/AUG/15','DD/MON/YY');
is used to specify that you wanna tell to Oracle a DATE type with value of 25th of August 2015, using a diffrent format, specified as second parameter. (DD/MM/YY in this case).
I am using Oracle10g database in which a table contains a Column with Date DataType. I am using the following query to get the record:
select to_char(START_TIME, 'YYMMDD HH24:MI:SS') from table;
So from above query, the result will be of type VARCHAR. I have tried to_Date() method but resulted in displaying only DATE. Can i convert VARCHAR to DATETIME format? The result should be of type DATETIME. Please help me how to resolve this problem.
an Oracle date contains both date and time so you can consider it a datetime (there is no datatype of datetime in Oracle). how is DISPLAYS when you select it is entirely up to your client. the default display setting is controlled by the NLS_DATE_FORMAT parameter. If you're just using the date in your pl/sql block then just assign it into a date datatype and select into that variable without to_char and it will work just fine and contain whatever time component is present in your table.
to control the display, for example using nls_date_format:
SQL> select a from datetest;
A
---------
19-FEB-13
SQL> alter session set nls_date_format='YYMMDD HH24:MI:SS';
Session altered.
SQL> select a from datetest;
A
---------------
130219 07:59:38
but again, this is only for display.
Oracle's Date type fields contain date/time values, therefore converting it to Datetime does not make any sense (it's already datetime)
Read more about oracle date types here
Yeah the Date datatype will meet your needs but you will have to jump through some hoops every time to get the exact time out of it. Definitely use the Timestamp datatype.
I am working (or fixing bugs) on an application which was developed in VS 2005 C#. The application saves data to a SQL server 2005. One of insert SQL statement tries to insert a time-stamp value to a field with GetDate() TSQL function as date time value.
Insert into table1 (field1, ... fieldDt) values ('value1', ... GetDate());
The reason to use GetDate() function is that the SQL server may be at a remove site, and the date time may be in a difference time zone. Therefore, GetDate() will always get a date from the server. As the function can be verified in SQL Management Studio, this is what I get:
SELECT GetDate(), LEN(GetDate());
-- 2010-06-10 14:04:48.293 19
One thing I realize is that the length is not up to the milliseconds, i.e., 19 is actually for '2010-06-10 14:04:48'. Anyway, the issue I have right now is that after the insert, the fieldDt actually has a date time value up to minutes, for example, '2010-06-10 14:04:00'. I am not sure why. I don't have permission to update or change the table with a trigger to update the field.
My question is that how I can use a INSERT T-SQL to add a new row with a date time value ( SQL server's local date time) with a precision up to milliseconds?
Check your table. My guess is that the FieldDT column has a data type of SmallDateTime which stores date and time, but with a precision to the nearest minute. If my guess is correct, you will not be able to store seconds or milliseconds unless you change the data type of the column.
I would guess that you are not storing the GetDate() value in a DateTime field. If you store the value in a datetime field you will get the maximum precision allowed by the DateTime type. Additionally, DateTime is a binary type (a double actually) so 19 means 19 bytes, not 19 characters.
Try to create a simple table with a Datetime field like this
CREATE TABLE [dbo].[DateTable](
[DateField] [datetime] NOT NULL
)
And add a date with
insert into datetable (datefield) values(getdate())
When you execute a select you will get back a value including milliseconds. The following query
select * from datetable
returns
2010-06-11 00:38:46.660
Maybe this would work instead of getdate -
SYSDATETIME()
look here if you can find what you need -
http://msdn.microsoft.com/en-us/library/ms188383.aspx
As you're on SQL 2005, don't forget the getutcdate() function to ensure that, regardless of where your servers are actually located, you have a constant time reference.
Imagine, you have the server in the UK in winter (i.e. GMT+0), and save a record at 10:30am. You then cut over to a SQL server hosted in California (GMT+8) and 8 hours later save another record.
Using getdate(), both saves record the same time "10:30:00". Using getutcdate(), the first save records at "10:30:00", the second save records "18:30:00".
Not really answering the question, but important in your circumstances.
You can use like this in procedure and If there is no procedure use only getdate().
insert into [dbo].[Tbl_User] (UserId,Uvendoremail,UAddress,Ddob,DMobile,
DEmail,DPassword,DAddress,CreatedDate) values (#userid,#vendoremail#address,#dob,#mobile,#email,#dpassword,#daddress,getdate())
How do we perform indexing on a datetime field in oracle. We should be able to search for a specific year
Thanks
To create an index in Oracle, use:
CREATE INDEX your_index_name ON your_table_name(your_column_name)
For more info about Oracle index creation, read this link.
Correction & Clarification
If you use a function to isolate a component of a date (IE: EXTRACT, or TRUNC), an index on the column will not help. But an index will help if you provide a date range:
WHERE your_date_column BETWEEN TO_DATE('2010-01-01', 'YYYY-MM-DD')
AND TO_DATE('2010-12-31', 'YYYY-MM-DD')
You can however create function based indexes in Oracle:
CREATE INDEX your_index_name
ON your_table_name(EXTRACT(YEAR FROM your_column_name))
...which DBAs loath with a passion.
You can index a DATE column (which stores date and time in Oracle) directly:
CREATE INDEX ix ON table (column)
Oracle will be able to use this index directly if you build your query so as to perform a RANGE SCAN. For example, if you want to retrieve rows from 2010:
SELECT ...
FROM table
WHERE column >= DATE '2010-01-01'
AND column < DATE '2011-01-01'
This index can also be used to answer queries for a specific month, day or any other range.
Add an index which is not bound to a column, but an expression that extract the year from that column:
create index sample_index on YourTable (extract(year from YourDateColumn)) tablesapce YourIndexSpace;
When you query the table using that expression, Oracle will use the index.
Just create index like shown above. DO NOT USE TRUNC FUNCTION, because it ignores any indexes. For instance, my datecreate field has next format 03.12.2009 16:55:52 So I used to use
trunc(datecreate, 'dd')=to_date(to_char(sysdate,'dd.mm.yyyy'),'dd.mm.yyyy')
and it worked very slowly(about 5 sec)!!! Now I use next expression:
datecreate>=to_date(to_char(sysdate,'dd.mm.yyyy'),'dd.mm.yyyy') and sw.datecreate<to_date(to_char(sysdate+1,'dd.mm.yyyy'),'dd.mm.yyyy')
and my query executes in 0,01 sec