SQL Server datetime LIKE select?

问题

in MySQL

select * from record where register_date like '2009-10-10%'

What is the syntax in SQL Server?

回答1:

You could use the DATEPART() function

SELECT * FROM record 
WHERE  (DATEPART(yy, register_date) = 2009
AND    DATEPART(mm, register_date) = 10
AND    DATEPART(dd, register_date) = 10)

I find this way easy to read, as it ignores the time component, and you don't have to use the next day's date to restrict your selection. You can go to greater or lesser granularity by adding extra clauses, using the appropriate DatePart code, e.g.

AND    DATEPART(hh, register_date) = 12)

to get records made between 12 and 1.

Consult the MSDN DATEPART docs for the full list of valid arguments.

回答2:

There's no direct support for LIKE operator against DATETIME variables, but you can always cast the DATETIME to a VARCHAR:

SELECT (list of fields) FROM YourTable
WHERE CONVERT(VARCHAR(25), register_date, 126) LIKE '2009-10-10%'

Check the MSDN docs for a complete list of available "styles" in the CONVERT function.

Marc

回答3:

If you do that, you are forcing it to do a string conversion. It would be better to build a start/end date range, and use:

declare @start datetime, @end datetime
select @start = '2009-10-10', @end = '2009-11-10'
select * from record where register_date >= @start
           and register_date < @end

This will allow it to use the index (if there is one on register_date), rather than a table scan.

回答4:

You can use CONVERT to get the date in text form. If you convert it to a varchar(10), you can use = instead of like:

select *
from record
where CONVERT(VARCHAR(10),register_date,120) = '2009-10-10'

Or you can use an upper and lower boundary date, with the added advantage that it could make use of an index:

select *
from record
where '2009-10-10' <= register_date
and register_date < '2009-10-11'

回答5:

Unfortunately, It is not possible to compare datetime towards varchar using 'LIKE' But the desired output is possible in another way.

    select * from record where datediff(dd,[record].[register_date],'2009-10-10')=0

回答6:

You can also use convert to make the date searchable using LIKE. For example,

select convert(VARCHAR(40),create_date,121) , * from sys.objects where     convert(VARCHAR(40),create_date,121) LIKE '%17:34%'

回答7:

The LIKE operator does not work with date parts like month or date but the DATEPART operator does.

Command to find out all accounts whose Open Date was on the 1st:

SELECT * 
  FROM Account 
 WHERE DATEPART(DAY, CAST(OpenDt AS DATE)) = 1`

*CASTING OpenDt because it's value is in DATETIME and not just DATE.

回答8:

There is a very flaky coverage of the LIKE operator for dates in SQL Server. It only works using American date format. As an example you could try:

... WHERE register_date LIKE 'oct 10 2009%'

I've tested this in SQL Server 2005 and it works, but you'll really need to try different combinations. Odd things I have noticed are:

You only seem to get all or nothing for different sub fields within the date, for instance, if you search for 'apr 2%' you only get anything in the 20th's - it omits 2nd's.
Using a single underscore '_' to represent a single (wildcard) character does not wholly work, for instance, WHERE mydate LIKE 'oct _ 2010%' will not return all dates before the 10th - it returns nothing at all, in fact!
The format is rigid American: 'mmm dd yyyy hh:mm'

I have found it difficult to nail down a process for LIKEing seconds, so if anyone wants to take this a bit further, be my guest!

Hope this helps.

回答9:

I am a little late to this thread but in fact there is direct support for the like operator in MS SQL server.

As documented in LIKE help if the datatype is not a string it is attempted to convert it to a string. And as documented in cast\convert documentation:

default datetime conversion to string is type 0 (,100) which is mon dd yyyy hh:miAM (or PM).

If you have a date like this in the DB:

2015-06-01 11:52:59.057

and you do queries like this:

select * from wws_invoice where invdate like 'Jun%'
select * from wws_invoice where invdate like 'Jun 1%'
select * from wws_invoice where invdate like 'Jun 1 %'
select * from wws_invoice where invdate like 'Jun 1 2015:%'
select * from wws_invoice where invdate like 'Jun ? 2015%'
...
select * from wws_invoice where invdate like 'Jun 1 2015 11:52AM'

you get that row.

However, this date format suggests that it is a DateTime2, then documentation says:

21 or 121 -- ODBC canonical (with milliseconds) default for time, date, datetime2, and datetimeoffset. -- yyyy-mm-dd hh:mi:ss.mmm(24h)

That makes it easier and you can use:

select * from wws_invoice where invdate like '2015-06-01%'

and get the invoice record. Here is a demo code:

DECLARE @myDates TABLE (myDate DATETIME2);
INSERT INTO @myDates (myDate)
VALUES
('2015-06-01 11:52:59.057'),
('2015-06-01 11:52:59.054'),
('2015-06-01 13:52:59.057'),
('2015-06-01 14:52:59.057');

SELECT * FROM @myDates WHERE myDate LIKE '2015-06-01%';
SELECT * FROM @myDates WHERE myDate LIKE '2015-06-01 11%';
SELECT * FROM @myDates WHERE myDate LIKE '2015-06-01 11:52:59%';
SELECT * FROM @myDates WHERE myDate LIKE '2015-06-01 11:52:59.054%';

Doing datetime searches in SQL server without any conversion to string has always been problematic. Getting each date part is an overkill (which unlikely would use an index). Probably a better way when you don't use string conversion would be to use range checks. ie:

select * from record 
where register_date >= '20091010' and register_date < '20091011';

回答10:

I solved my problem that way. Thank you for suggestions for improvements. Example in C#.

string dd, mm, aa, trc, data;
dd = nData.Text.Substring(0, 2);
mm = nData.Text.Substring(3, 2);
aa = nData.Text.Substring(6, 4);
trc = "-";
data = aa + trc + mm + trc + dd;

"Select * From bdPedidos Where Data Like '%" + data + "%'";

来源：https://stackoverflow.com/questions/1629050/sql-server-datetime-like-select

标签

sql-server

sql-like