Using SQLCe, I have a column of DateTime type. I would like to filter just by year. Is it possible or should I store year separately, which seems to me redundant?
E.g. get distinct results of 2010,2011,2013.
Thanks
think you have the DATEPART function (but not the YEAR function)
so
select DatePart(yyyy, <yourDateTime>)
or if that's for ordering, of course
order by DatePart(yyyy, <yourDatetime>)
EDIT
select max(InvoiceID)
from yourTable
where DatePart(yyyy, IssuedDate) = 2013
You can use the DATEPART function to return the year for that column:
SELECT DATEPART(yyyy, datetimecolumn) FROM YourTable
You can then filter with a where clause:
WHERE datetimecolumn = 2014
The usual way to do this is to use a range filter:
select *
from table
where datecolumn >= '2012/01/01' and datecolumn < '2013/01/01'
This has the benefit that any index you may have on datecolumn can be used.
Since the answer you accepted shows that you only care about one single year, your objection to this answer doesn't really apply.
select max(InvoiceID)
from table
where IssuedDate >= '2012/01/01' and IssuedDate < '2013/01/01'
will work just fine.
Related
I'm trying to get a list of years from a date field that's stored as an nvarchar so am thinking doing a subquery to convert the date then select the year is the best way to go but having a hard time setting it up.
select datepart(yyyy,
(
SELECT convert(date,'21-02-12 6:10:00 PM',5) datenum
)
) as [year]
from SalesReport_AllDBs
group by datepart(yyyy, [datenum])
Any advice would be helpful to get this set up correctly
The subquery should go in your FROM clause:
SELECT datepart(yyyy, mydate) as datenum
FROM (SELECT convert(date, yourdatestringfield ,5) as myDate FROM SalesReport_AllDBs) as years
GROUP BY datepart(yyyy,mydate);
Or in one query without a subquery, which is a lot nicer looking:
SELECT datepart(convert(date, yourdatestringfield ,5)) as datenum
FROM SalesReport_AllDBs
GROUP BY datenum
You should really just fix the table to hold dates instead of strings though. This is just going to lead to some nightmare scenarios and a slow slow query.
select distinct year(cast([datenum] as date)) year
from SalesReport_AllDBs
Is there some tricky way to GROUP BY a variable which has been defined by alias or which is a result of calculation? I think that the following code makes a double dip by calculating MyMonth in Select statement and then again in Group statement. It may be unnecessary waste. It is not possible by simple GROUP BY MyMonth. Is it possible to force only one calculation of month([MyDate])?
Update of code. Aggregate function is added.
SELECT month([MyDate]) AS MyMonth, count([MyDate]) AS HowMany
FROM tableA
WHERE [MyDate] BETWEEN '2014-01-01' AND '2014-12-31'
GROUP BY month([MyDate])
ORDER BY MyMonth
Your real problem likely stems from calling MONTH(...) on every row. This prevents the optimizer from using an index to fulfill the count (it can use it for the WHERE clause, but this will still be many rows).
Instead, you should turn this into a range query, that the optimizer could use for comparisons against an index. First we build a simple range table:
WITH Months as (SELECT MONTH(d) AS month,
d AS monthStart, DATEADD(month, 1, d) AS monthEnd
FROM (VALUES(CAST('20140101' AS DATE))) t(d)
UNION ALL
SELECT MONTH(monthEnd),
monthEnd, DATEADD(month, 1, monthEnd)
FROM Months
WHERE monthEnd < CAST('20150101' AS DATE))
SQL Fiddle Example
(if you have an existing calendar table, you can base your query on that, but sometimes a simple ad-hoc one works best)
Once we have the range-table, you can then use it to constrain and bucket your data, like so:
SELECT Months.month, COUNT(*)
FROM TableA
JOIN Months
ON TableA.MyDate >= Months.monthStart
AND TableA.MyDate < Months.monthEnd
GROUP BY Months.month
Note: The start of the date range was changed to 2014-01-01, as it seems strange that you'd only include one day from January, when aggregating months...
No, you can't use column alias directly in the GROUP BY clause. Instead do a select in the from list, and use the result column in your group by.
select MyMonth, MAX(someothercolumn)
from
(
SELECT month([MyDate]) AS MyMonth,
someothercolumn
FROM tableA
WHERE [MyDate] BETWEEN '2014-01-31' AND '2014-12-31'
)
GROUP BY MyMonth
ORDER BY MyMonth
I have a table that contains records with a column indicates the Date. Given a record, I would like to select all records that are in the same week as the record. How can SQL do that?
I should say that I'm using SQLite.
You can use DATEPART with wk to get the current week. Then just check for equality.
In this case, I have also checked yy to make sure that you do not check the year of a previous week.
SELECT *
FROM TABLE
WHERE DATEPART(wk, TABLE.DATECOLUMN)
= DATEPART(wk, (SELECT DATECOLUMN FROM TABLE WHERE ID = GivenID))
AND DATEPART(yy, TABLE.DATECOLUMN) = DATEPART(yy, (SELECT DATECOLUMN FROM TABLE WHERE ID = GivenID))
UPDATE FOR SQLITE
To do this in SQLLite, Refer to this SO question and then this article that states %W is what you use to get week and %Y for year. Which gives you:
SELECT *
FROM TABLE
WHERE STRFTIME('%W', TABLE.DATECOLUMN)
= STRFTIME('%W', (SELECT DATECOLUMN FROM TABLE WHERE ID = GivenID))
AND STRFTIME('%Y', TABLE.DATECOLUMN)
= STRFTIME('%Y', (SELECT DATECOLUMN FROM TABLE WHERE ID = GivenID))
Use the datediff() function:
datediff(ww,start_date,end_date) < 1
You can use BETWEEN to specify the records you want.
SELECT * FROM records WHERE datecolumn between 'YYYY/MM/DD' AND 'YYYY/MM/DD'
So I have a table that has the month and year broken down, for example field called Month has the number 7 in it (this month) and the Year field has 2011. Theres also additional months years, etc. How can I query this to show just the current year, month?
In SQL Server you can use YEAR, MONTH and DAY instead of DATEPART.
(at least in SQL Server 2005/2008, I'm not sure about SQL Server 2000 and older)
I prefer using these "short forms" because to me, YEAR(getdate()) is shorter to type and better to read than DATEPART(yyyy, getdate()).
So you could also query your table like this:
select *
from your_table
where month_column = MONTH(getdate())
and year_column = YEAR(getdate())
This should work for SQL Server:
SELECT * FROM myTable
WHERE month = DATEPART(m, GETDATE()) AND
year = DATEPART(yyyy, GETDATE())
This should work in MySql
SELECT * FROM 'my_table' WHERE 'month' = MONTH(CURRENT_TIMESTAMP) AND 'year' = YEAR(CURRENT_TIMESTAMP);
How about:
Select *
from some_table st
where st.month = to_char(sysdate,'MM') and
st.year = to_char(sysdate,'YYYY');
should work in Oracle. What database are you using? I ask because not all databases have the same date functions.
DECLARE #CMonth int=null
DECLARE #lCYear int=null
SET #lCYear=(SELECT DATEPART(YEAR,GETDATE()))
SET #CMonth=(SELECT DATEPART(MONTH,GETDATE()))
select *
from your_table
where MONTH(mont_year) = MONTH(NOW())
and YEAR(mont_year) = YEAR(NOW());
Note: (month_year) means your column that contain date format. I think that will solve your problem. Let me know if that query doesn't works.
I want to list all sales, and group the sum by day.
Sales (saleID INT, amount INT, created DATETIME)
NOTE: I am using SQL Server 2005.
if you're using SQL Server,
dateadd(DAY,0, datediff(day,0, created)) will return the day created
for example, if the sale created on '2009-11-02 06:12:55.000',
dateadd(DAY,0, datediff(day,0, created)) return '2009-11-02 00:00:00.000'
select sum(amount) as total, dateadd(DAY,0, datediff(day,0, created)) as created
from sales
group by dateadd(DAY,0, datediff(day,0, created))
For SQL Server:
GROUP BY datepart(year, datefield),
datepart(month, datefield),
datepart(day, datefield)
or faster (from Q8-Coder):
GROUP BY dateadd(DAY, 0, datediff(day, 0, created))
For MySQL:
GROUP BY year(datefield), month(datefield), day(datefield)
or better (from Jon Bright):
GROUP BY date(datefield)
For Oracle:
GROUP BY to_char(datefield, 'yyyy-mm-dd')
or faster (from IronGoofy):
GROUP BY trunc(created);
For Informix (by Jonathan Leffler):
GROUP BY date_column
GROUP BY EXTEND(datetime_column, YEAR TO DAY)
If you're using MySQL:
SELECT
DATE(created) AS saledate,
SUM(amount)
FROM
Sales
GROUP BY
saledate
If you're using MS SQL 2008:
SELECT
CAST(created AS date) AS saledate,
SUM(amount)
FROM
Sales
GROUP BY
CAST(created AS date)
For PostgreSQL:
GROUP BY to_char(timestampfield, 'yyyy-mm-dd')
or using cast:
GROUP BY timestampfield::date
if you want speed, use the second option and add an index:
CREATE INDEX tablename_timestampfield_date_idx ON tablename(date(timestampfield));
actually this depends on what DBMS you are using but in regular SQL convert(varchar,DateColumn,101) will change the DATETIME format to date (one day)
so:
SELECT
sum(amount)
FROM
sales
GROUP BY
convert(varchar,created,101)
the magix number 101 is what date format it is converted to
If you're using SQL Server, you could add three calculated fields to your table:
Sales (saleID INT, amount INT, created DATETIME)
ALTER TABLE dbo.Sales
ADD SaleYear AS YEAR(Created) PERSISTED
ALTER TABLE dbo.Sales
ADD SaleMonth AS MONTH(Created) PERSISTED
ALTER TABLE dbo.Sales
ADD SaleDay AS DAY(Created) PERSISTED
and now you could easily group by, order by etc. by day, month or year of the sale:
SELECT SaleDay, SUM(Amount)
FROM dbo.Sales
GROUP BY SaleDay
Those calculated fields will always be kept up to date (when your "Created" date changes), they're part of your table, they can be used just like regular fields, and can even be indexed (if they're "PERSISTED") - great feature that's totally underused, IMHO.
Marc
For oracle you can
group by trunc(created);
as this truncates the created datetime to the previous midnight.
Another option is to
group by to_char(created, 'DD.MM.YYYY');
which achieves the same result, but may be slower as it requires a type conversion.
The simplest and intuitive solution for MySQL is:
GROUP BY day(datefield)
use linq
from c in Customers
group c by DbFunctions.TruncateTime(c.CreateTime) into date
orderby date.Key descending
select new
{
Value = date.Count().ToString(),
Name = date.Key.ToString().Substring(0, 10)
}