I need to perform a date search but the data is a String with the format
'dd/mm/yyyy'
I want to search only for 'mm/yyyy'
For example I want all records that have '07/2014' regardless of what day?
I'm sure its something simple just can't figure it out
EDIT:
It looks like the format is MM/DD/YYY
Looks like I got this sorted just used:
RIGHT(BookedDate,5) = '/2014'
AND LEFT (BookedDate,2) = '7/'
Thanks All :)
If your string is in the format of dd/mm/yyyy always, as in 01/09/2014 you could use right:
declare #val as varchar(10)
Set #val='1/2/2014'
RIGHT(#val,7)
if you are not sure of the format but know that there is a / you could search for it:
declare #val as varchar(10)
Set #val='1/2/2014'
select right(#val,len(#val)-patindex('%/%',#val))
myfield like '%/07/2014'
Beware, since the wildcard (%) is put at the beginning of the query no indexes (if they exist) will be used. This will always be a full table scan.
If you store your date values in character based column, than jyparask's answer is good enough, but if you store it in date/time based column, then use date/time functions or intervals:
WHERE
myDateColumn >= '01/07/2014'
AND myDateColumn < '01/08/2014'
The above WHERE condition means: all values in July, 2014.
This will ensure that, because its a string, if the value is longer than expected the first three characters will always be removed.
SELECT RIGHT(field, LEN(field)-3) FROM database
This feels like a very bad idea. Most likely there is a ton of optimizations that could be done automatically for your queries by the database if you used Date instead of the String.
This is certainly going to be some kind of bottleneck if your database grows, it would have to ask and parse every single row to find out if it matches your request.
Related
I should preface my question by saying I am very new to SQL (or any programming involving databases). I started learning SQL a couple of weeks ago when I decided to take on a data project.
I have been using SSMS in wrangling large tables in comma-separated text file format. I need to be able to sort by dates, and the current format is mmddyyyy, but when I try to sort by date it does not work.
I know that converting dates is something that gets asked a lot around here, but I haven't found any solutions that explain things for a newb like myself.
So far my guesses for a solution are to use the CONVERT or CAST solutions, but I'm not sure if that is the right approach. I have found several CAST/CONVERT posts but none have really applied to my situation.
I hate to have this as my first question, but I'd thought I'd take some down vote bullets if it means I could figure this out. Thank you.
Sample of what I'm trying to do:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE [ column1] > 01012017;
I get the entire table back, unsorted.
Since your:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE [ column1] > 01012017;
does not error, we could say that the [column1]'s datatype is either a character type (like VARCHAR, char), or datetime.
Since you are getting back all the data and I would think you don't have data in the future, it should be a varchar (or char) - with datetime that means 1900-01-01 + 1012017 days.
To make it a datetime you need to 'cast' your column1 which is in mmddyyyy form by first converting it to yyyymmdd style (which would work under any date and language setting):
cast(right([column1],4)+substring([column1],1,2)+substring([column1],3,2) as datetime)
and you would write that 01012017 as a string (quotes around) and also again in yyyymmdd format (it would be implicitly casted to datetime):
'20170101'
So your SQL becomes:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE cast(right([column1],4) +
substring([column1],1,2) +
substring([column1],3,2) as datetime) > '20170101';
Having a date\datetime column as varchar and using like this would render the ability to use simple indexes but that is another matter. For now, this would return the data you want.
Assuming your column's datatype is [Date], try something similar to:
SELECT *
FROM [databasename].[dbo].[table1]
WHERE FORMAT([column1],'dd/MM/yyyy') >'01012017'
If it's string format, you'll have to use CONVERT() to convert the column to Date with a query like
SELECT *
FROM [databasename].[dbo].[table1]
WHERE CONVERT(NVARCHAR(10), [Column1], 112) >'01012017'
Refer to this W3Schools article if you need more help with the CONVERT clause
There is this strange error in sql query.
The query is something like this.
select * from student where dob between '20150820' and '20150828'
But in the database the column of dob is varchar(14) and is in yyyyMMddhhmmss format,Say my data in the row is (20150827142545).If i fire the above query it should not retrive any rows as i have mentioned yyyyMMdd format in the query.But it retrives the row with yesterday date (i.e 20150827112535) and it cannot get the records with today's date (i.e 20150828144532)
Why is this happening??
Thanks for the help in advance
You can try like this:
select * from student
where convert(date,LEFT(dob,8)) between
convert(date'20150820') and convert(date,'20150828'))
Also as others have commented you need to store your date as Date instead of varchar to avoid such problems in future.
As already mentioned you would need to use the correct date type to have between behave properly.
select *
from student
where convert(date,LEFT(dob,8)) between '20150820' and '20150828'
Sidenote: You don't have to explicitly convert your two dates from text as this will be done implicitly as long as you use an unambiguous date representation, i.e. the ISO standard 'YYYYMMDD' or 'YYYY-MM-DD'. Of course if you're holding the values in variables then use date | datetime datatype
declare #startdate date
declare #enddate date
select *
from student
where convert(date,LEFT(dob,8)) between #startdate and #enddate
Sidenote 2: Performing the functions on your table dob column would prevent any indexes on that column from being used to their full potential in your execution plan and may result in slower execution, if you can, define the correct data type for the table dob column or use a persistent computed column or materialised view if your performance is a real issue.
Sidenote 3: If you need to maintain the time portion in your data i.e. date and time of birth, use the following to ensure all records are captured;
select *
from student
where
convert(date,LEFT(dob,8)) >= '20150820'
and convert(date,LEFT(dob,8)) < dateadd(d,1,'20150828')
All you have to do is to convert first the string to date.
select *
from student
where dob between convert(date, '20150820') and convert(date, '20150828')
Why is this happening?
The comparison is executed from left to right and the order of characters is determined by the codepage in use.
Sort Order
Sort order specifies the way that data values are sorted, affecting
the results of data comparison. The sorting of data is accomplished
through collations, and it can be optimized using indexes.
https://msdn.microsoft.com/en-us/library/ms143726.aspx
There are problems with between in T-SQL.
But if you want a fast answer convert to date first and use >= <= or even datediff to compare - maybe write a between function yourself if you want the easy use like between and no care about begin and start times ...
What do BETWEEN and the devil have in common?
I've got a seamingly simple problem to solve that normally would be fairly easy. I've got a field that contains a DateTime portion, as well as a trailing text portion. I now need to split this field into two discrete fields - DateTime and Varchar. Now for the little gotcha. The data has been saved with two different date formats which has resulted in the filed looking a 'lot' like this:
amendmentnote
----------------------------------------------------------------------
30/07/2010 11:39:55: Booking status change from On Option to Cancelled
5/5/2010 10:1:8 : New
as you can see, the dates are in two completely different formats. I'd like to somehow see it parsed out as:
dateofnote | note
----------------------------------------------------------------------
30/07/2010 11:39:55 | Booking status change from On Option to Cancelled
05/05/2010 10:01:08 | New
is this easily do-able??
cheers
jim
Easily? No. Do-able. Yes, if we can make some assumptions. If it is the case that the text never contains a colon, you could do:
Declare #Data Table ( Data Varchar(max) )
Insert #Data(Data) Values('30/07/2010 11:39:55: Booking status change from On Option to Cancelled')
Insert #Data(Data) Values('5/5/2010 10:1:8 : New')
Set DateFormat DMY
Select Cast(Reverse(Substring(Reverse(Data), CharIndex(':', Reverse(Data)) + 1, Len(Data))) As DateTime)
, LTrim(Reverse(Substring(Reverse(Data), 1, CharIndex(':', Reverse(Data)) - 1)))
From #Data
It's do-able, but it'll be ugly.
You can use string functions to find the third colon in the amendmentnote field, and anything to the right of the third colon will be your note.
As for the date, you should again be able to use string functions to reformat the date portion, although you'll most likely need lots of substrings to make it work.
My only concern would be if the date formats entered are MM/DD/YYYY for one entry, and DD/MM/YYYY for the other.
Based on what's provided, use:
SELECT CONVERT(DATETIME,
SUBSTRING(t.amendmentnote, 1, LEN(SUBSTRING(t.amendmentnote, 1, PATINDEX('%: %', t.amendmentnote)))-1),
103),
LTRIM(SUBSTRING(t.amendmentnote,
LEN(SUBSTRING(t.amendmentnote, 1, PATINDEX('%: %', t.amendmentnote)))+1,
LEN(t.amendmentnote)))
FROM YOUR_TABLE t
Being a DATETIME, you can use CAST/CONVERT to format it as you like - don't store "presentation" data.
Bad data is bad data - this is a mine field you'll have to navigate, isolating rows that won't match the pattern in the query & deal with appropriately.
Once in a DateTime column, they'll be in the standard DateTime format. How they're presented once queried at that point is up to you.
So, once you split your data into your DateOfNote and Note columns, you can Convert the DateOfNote to VarChar and apply a format to get what you want.
Convert(NVARCHAR, DateOfNate, 103) will get you there (I think: double check the format style there at the end).
Edit Based on your question, it looks like you wanted more help with the formatting. However, on the splitting the column, you'll need to use string functions. I'd find the index of that last colon, store it in a local variable, and then use substring to find the datetime (left of that last colon) and the note (right of last colon).
I have a value in field called "postingdate" as string in 2009-11-25, 12:42AM IST format, in a table named "Post".
I need the query to fetch the details based on date range. I tried the following query, but it throws an error. Please guide me to fix this issue. Thanks in advance.
select postingdate
from post
where TO_DATE(postingDate,'YYYY-MM-DD')>61689
and TO_DATE(postingDate,'YYYY-MM-DD')<61691
As you've now seen, trying to perform any sort of query against a string column which represents a date is a problem. You've got a few options:
Convert the postingdate column to some sort of DATE or TIMESTAMP datatype. I think this is your best choice as it will make querying the table using this field faster, more flexible, and less error prone.
Leave postingdate as a string and use functions to convert it back to a date when doing comparisons. This will be a performance problem as most queries will turn into full table scans unless your database supports function-based indexes.
Leave postingdate as a string and compare it against other strings. Not a good choice as it's tough to come up with a way to do ranged queries this way, as I think you've found.
If it was me I'd convert the data. Good luck.
In SQL Server you can say
Select postingdate from post
where postingdate between '6/16/1969' and '6/16/1991'
If it's really a string, you're lucky that it's in YYYY-MM-DD format. You can sort and compare that format as a string, because the most significant numbers are on the left side. For example:
select *
from Posts
where StringDateCol between '2010-01-01' and '2010-01-02'
There's no need to convert the string to a date, comparing in this way is not affected by the , 12:42AM IST appendage. Unless, of course, your table contains dates from a different time zone :)
You will need to convert your string into a date before you run date range queries on it. You may get away with just using the string if your not interested in the time portion.
The actual functions will depend on your RDBMS
for strings only
select * from posts
where LEFT(postingDate,10) > '2010-01-21'
or
for datetime ( Sybase example)
select * from posts
where convert(DateTime,postingDate) between '2010-01-21' and '2010-01-31'
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?