Need to transfer numeric columns with numbers like '201 711' and '201 806' to dates like '2017-11-01' and '2018-06-01' ('YYYY-MM-01'). When I try this
select to_date(debt_max_period,'YYYY-MM') as date1 from debt;
I get
SQL Error [42883]: ERROR: function to_date(numeric, unknown) does not
exist.
Will be thankful for any ideas!
You need to cast the number to a text/varchar value. As the number doesn't contain the - character, you also need to remove that from your format mask.
to_date(debt_max_period::text, 'yyyymm')
Oracle -
select TO_CHAR(TO_DATE(START_DATE,'YYYYMMDD'),'YYYY-MM-DD') STARTDATE from account
You can use like below as well.
Postgresql -
select TO_CHAR(TO_DATE(START_DATE::text,'YYYYMMDD'),'YYYY-MM-DD') STARTDATE from account
Related
I am getting the following error message, when trying to convert timestamp column to time.
Error message:
SQL Error [500310] [0A000]: [Amazon](500310) Invalid operation: Specified types or functions (one per INFO message) not supported on Redshift tables.
Here is my sql snippets I have been using to convert the column over, but all give me the above error:
SELECT pg_catalog.time(timestamp) AS myTime from tableA.time
SELECT "time"(timestamp) AS myTime from tableA.time
SELECT to_char(cast(timestamp as "time")) from tableA.time
select timestamp::time from tableA.time
What has worked for me but what I do not need, since I need to run mathematical operations on the time, is below the sql scripts.
SELECT
EXTRACT(HOUR FROM timestamp) AS HOUR,
EXTRACT(MINUTE FROM timestamp) AS MINUTE,
EXTRACT(SECOND FROM timestamp) AS SECOND
FROM tableA.time;
is there any way I could check the properties of the column to see if the reason the column is not converting to time? I have tried simple lines like this (select '2016-10-01 12:12:12'::time) that work perfectly fine not sure why the whole column is not converting over. If anyone could provide me some help that would be great!
thank you in advance.
-EDIT-
I looked at the column with the timestamp and the type of the column is "timestamp without time zone". Maybe that is what is causing the error.
I have a column saved as a character data type. This column is what I am going to be using as a date. The column goes "YYYY-MM-DD" in that format.
This is a problem because if I ever need to filter by date, I have to go
select col_1, col_2
from table
where date LIKE '2016-04%;
If I want to search for a date range, this turns into a giant complicated mess.
What is the easiest way to convert this to a "date" data type? I want it to continue to be in YYYY-MM-DD order (no timestamp).
My ultimate goal is to be able to search for dates in a format like this:
select col_1, col_2
from table
where date between 2016-01-01 AND 2016-05-31;
What do you guys recommend? I am terrified I am going to corrupt my date if I use an alter statement to convert my data type. (I have a copy of the data saved and can upload it again, but it will take forever.)
Edit: This is a VERY Large table.
Edit Part 2: I originally stored the data as a varchar data type because my dates were not uploading correctly and I got an error message when I tried to save as a date data type. The every date in this column is in the "YYYY-MM-DD" order. My solution was to save it as varchar to avoid the error message (I couldn't figure out what was wrong. I even got rid of leading and trailing spaces.)
Storing a date as a varchar was the wrong choice to begin with. It's very good that you want to change that.
The first step is to convert the columns using an ALTER TABLE statement:
alter table the_table
ALTER COLUMN col_1 TYPE date using col_1::date,
ALTER COLUMN col_2 TYPE date using col_2::date;
Note that this will fail if you have any value in those columns that cannot be convert to a correct date. If you get that you need to first fix those invalid strings before you can change the data type.
I want it to continue to be in YYYY-MM-DD order
This is a misconception. A DATE (or timestamp) does not have a "format". Once it's stored as a date you can display it in any format you want.
My ultimate goal is to be able to search for dates in a format like this:
2016-01-01 is not a valid date literal, a proper (i.e. correctly typed) date constant can be specified e.g. using date '2016-01-01' (note the single quotes!
So your query becomes:
select col_1, col_2
from table
where col_1 between date '2016-01-01' AND date '2016-05-31';
If you have a lot of queries like that you should consider creating an index on the date columns.
Regarding the date constant format:
Are you telling me that despite having the varchar data types, I can still (as of right now) search between specific dates by just typing the word date and putting single quotes between two dates
No, that's not the case. SQL is a strongly typed language and as such will only compare values of the same type.
Using an ANSI date literal (or e.g. to_date()) results in a type constant (i.e. a value with a specific data type).
The difference between date '2016-01-01' and '2016-01-01' is the same as between42(a number) and'42'` (a string).
If you compare a string with a date, you are comparing apples and oranges and the database will do an implicit data type conversion from one type to the other. This is something that should be avoided at all costs.
If you do not want to change the table, you should use the query sagi provided which explicitly converts the strings to dates and then does the comparison on (real) date values (not strings)
You can use POSTGRES TO_DATE() cast function :
SELECT col_1,col_2
FROM Your_Table
WHERE to_date(date_col,'yyyy-mm-dd') between to_date('2016-05-31','yyyy-mm-dd') and to_date('2016-01-01','yyyy-mm-dd')
What #a_horse said.
Plus, if you can't change the data type for some odd reason, to_date() is a safe option to convert the column on the column, but there is no point to use the same expression for provided constants. So:
SELECT col_1, col_2
FROM tbl
WHERE to_date(date, 'YYYY-DD-MM') BETWEEN date '2016-05-31' AND date '2016-01-01';
Or just use string literals without type. The type date is deferred from the context in this expression. And you don't even need to_date(). Since you are using ISO format already. A plain cast is safe:
WHERE date::date BETWEEN '2016-05-31' AND '2016-01-01';
Be sure to use ISO 8601 format for all date strings, so they are unambiguous and valid with any locale.
You can even have an expression index to support the query. Match the actual expression used in queries:
CREATE INDEX tbl_date_idx ON tbl ((date::date)); -- parentheses required!
But I wouldn't use the basic type name date as identifier to begin with.
The timestamp has milliseconds, so if any records are created via automation they will likely have the same seconds value but different millisecond values. I need to do this:
Version.uniq(:created_at)
But, this doesn't work because they are all unique. How can I use to_i, or whatever else might work, to pull this off?
You'll need the date_trunc() PostgreSQL function:
SELECT DISTINCT date_trunc('second', created_at) FROM "version"
In ruby:
Version.select("date_trunc('second', created_at)").distinct
To just get rid of fractional seconds, cast to the equivalent type with 0 fractional digits.
SELECT DISTINCT created_at::timestamp(0) FROM "version"
Or timestamptz, you did not disclose your exact type.
For more specific needs use date_trunc().
More details:
Discard millisecond part from timestamp
I have created a table with a column date_time type (varchar2 (40) ) but when i try to insert the current system date and time the doesnt work it gives error (too many values). please tell me what's wrong with the insert statement.
create table HR (type varchar2 (20), raised_by number (6), complaint varchar2 (500), date_time varchar2(40))
insert into HR values ('request',6785,'good morning',sysdate,'YYYY/MM/DD:HH:MI:SSAM')
The immediate cause of the error is that you have too many values, as the message says; that is, more elements in your values clause than there are columns. It is better to explicitly list the column names to avoid future problems and confusion, so you're really doing this:
insert into HR (type, raised_by, complaint, date_time)
values ('request',6785,'good morning',sysdate,'YYYY/MM/DD:HH:MI:SSAM')
... sp you have four columns, but five values. You're trying to insert the current date/time as a string so you would need to use the to_char() function:
insert into HR (type, raised_by, complaint, date_time)
values ('request',6785,'good morning',
to_char(sysdate,'YYYY/MM/DD:HH:MI:SSAM'))
But it is bad practice to store a date (or any other structured data, such as a number) as a string. As the documentation notes:
Each value manipulated by Oracle Database has a data type. The data
type of a value associates a fixed set of properties with the value.
These properties cause Oracle to treat values of one data type
differently from values of another. For example, you can add values of
NUMBER data type, but not values of RAW data type.
If you use a string then you can put invalid values in. If you use a proper DATE data type then you cannot accidentally put an invalid or confusing value in. Oracle will also be able to optimise the use of the column, and will be able to compare values safely and efficiently. Although the format you're using is better than some, using string comparison you still can't easily compare two values to see which is earlier, so you can't properly order by the date_time column for example.
Say you inserted two rows with values 2013/11/15:09:00:00AM and 2013/11/15:08:00:00PM - which is earlier? You need to look at the AM/PM marker to realise the first one is earlier; with a string comparison you'd get it wrong because 8 would be sorted before 9. Using HH24 instead of HH and AM avoids that, but would still be less efficient than a true date.
If you need to store a date with a time component you can use the DATE data type, which has precision down to the second; or if you need fractional seconds too then you can use TIMESTAMP. Then your table and insert would be:
create table HR (type varchar2 (20), raised_by number (6),
complaint varchar2 (500), date_time date);
insert into HR (type, raised_by, complaint, date_time)
values ('request',6785,'good morning',sysdate);
You can still get the value in the format you wanted for display purposes as part of a query:
select type, raised_by, complaint,
to_char(date_time, 'YYYY/MM/DD:HH:MI:SSAM') as date_time
from HR
order by date_time;
TYPE RAISED_BY COMPLAINT DATE_TIME
-------------------- ---------- -------------------- ---------------------
request 6785 good morning 2013/11/15:08:44:35AM
Only treat a date as a string for display.
You can use TO_DATE() or TO_TIMESTAMP or To_char() function,
insert into HR values ('request',6785,'good morning',TO_DATE(sysdate, 'yyyy/mm/dd hh24:mi:ss'))
insert into HR values ('request',6785,'good morning',TO_TIMESTAMP(systimestamp, 'yyyy/mm/dd hh24:mi:ss'))
sysdate - It will give date with time.
systimestamp - It will give datetime with milliseconds.
To_date() - Used to convert string to date.
To_char() - Used to convert date to string.
Probably here you have to use To_char() because your table definition have varchar type for date_time column.
Use TIMESTAMP datatype for date_time. And while inserting use the current timestamp.
create table HR (type varchar2(20), raised_by number(6), complaint varchar2(500), date_time timestamp);
insert into HR values ('request',6785,'good morning', systimestamp);
For other options: http://psoug.org/reference/timestamp.html
I have a subquery which converts a text coloumn into datetime. Since it is in text format there are coloumns wich contains bad data. I know the first answer would be to correct the data, I strongly agree that. I do not have the privileges to do that, unfortunately i have to deal with it.
below is my query
INNER JOIN TABLE XYZ
ON XYZ.COLOUMN1=YZX.COLOUMN2
LEFT JOIN ( SELECT ABC.stu_id
ABC.stu_name
CONVERT(DATETIME,LMN.startDate,111) STARTDATE
CONVERT(DATETIME,LMN.endDate,111) ENDDATE
FROM STUDENT ABC
INNER JOIN AN_STUDENT_TABLE LMN
ON ABC.stu_id=LMN.stu_id
WHERE ISDATE(startDate)=1
AND ISDATE(endDate)=1
GROUP BY ABC.stu_id,ABC.stu_name,STARTDATE,ENDDATE) DIN ON DIN.stu_id=LMNOP.stu_id
WHERE e.date BETWEEN DIN.STARTDATE AND DIN.ENDDATE
when i compare e.date with the startdate and enddate it fails giving me an well know error
"The conversion of a varchar data type to a datetime data type resulted in an out-of-range value."
what can be done to atleast skip those bad data records which cannot be converted?
I tried my best to figure this out but failed. Any help/advice appretiated!
Your ISDATE in the where clause does not necessarily filter out the bad dates before they are used in the conversion.
I think you should do this in two steps. First create a temp table or table variable that holds the rows from STUDENT where startDate and endDate is correct (use ISDATE for this) and then use that table in your actual query.