Todays date minus a number from a integer field - sql

Im new to SQL. I have a field (ContractDays) with an integer (number of days from a datediff) and want to create a date field with a value of todays date minus the number in ContractDays field. Can you help please?

If you are using mssql. You can do this:
SELECT DATEADD(day, -ContractDays, GETDATE())
FROM Table1

MS SQL contains datetime as number value. Integer part is number of days since 1/1/1753.
So you can write
select GetDate() - ContractDays
But it is better to use DATEADD

You need to alter the table in Oracle, MySQL or MS SQL to add a new column, let's call it ContractDate.
After you have this column, you need to update it to have the correct value.
Oracle:
update Contracts
set ContractDate = (SYSDATE - ContractDays)
MySQL:
update Contracts
set ContractDate = date_add(now(), INTERVAL -ContractDays DAY)
MS SQL (courtesy to Arion):
update Contracts
set ContractDate = DATEADD(day, -ContractDays, GETDATE())

Related

query to select data from this day [duplicate]

This question already has answers here:
In SQL Server, what is the best way to filter items for an entire day
(3 answers)
Closed 8 years ago.
I have a database table that has Datelogged columns from type Datetime (Sql server 2008 r2)
The Datelogged value is like this 2014-10-22 12:57:36.583
I want to do a query to select all the rows that its date is today (I care about year, month, and day) but not (hour, second.)
This is my query
string query = "SELECT * FROM Orders WHERE PrintTime is NULL WHERE Datelogged = #Datelogged";
but I didn't know what should I do to tell the query to compare just on year-month-day
Based on #Aaron Bertrand comment
It appears that it is better to use a Date Range from current day midnight (00:00:00) to < tomorrow at midnight.
Query copied from his comment.
DateLogged >= CONVERT(DATE, #DateLogged) AND
DateLogged < DATEADD(DAY, 1, CONVERT(DATE, #DateLogged))
Also see: Bad habits to kick : mis-handling date / range queries By Aaron Bertrand
(Old Answer)
You can use CONVERT(DATE, Datelogged) to get Date part without time.
"SELECT * FROM Orders WHERE PrintTime is NULL AND CONVERT(DATE, Datelogged) = #Datelogged"
Make sure you pass the parameter value using Date property in C# like:
cmd.Paramaters.AddWithValue("#Datelogged", DateTime.Today);// or DateTime.Now.Date
Also make sure to remove multiple WHERE from your query and use AND or OR to combine two conditions depending on your requirement.
Get the minimum date time range for current date and maximum date time range for today. Then, compare it with the logged date value.
Conversion operator on any table column adds extra conversion overhead and leads to inefficient use of index. Should be avoided when possible.
SELECT * FROM Orders
WHERE PrintTime is NULL
AND (Datelogged > dateadd(DD, -1, cast( GETDATE() as date)) AND Datelogged < dateadd(DD, 1, cast( GETDATE() as date)));

Getting year of timestamp in PostgreSQL

I have table called TrainingMatrix and it has a column called ExpiryDate. I am trying to write an SQL statement which can show me all records of 2012 as following:
SELECT * FROM "TrainingMatrix" WHERE "ExpiryDate" - current_date < 0 AND EXTRACT(YEAR FROM TIMESTAMP "ExpiryDate") = 2012;
But this doesn't work, can any one help?
I am using PostgreSQL.
No timestamp word when using column:
... AND EXTRACT(YEAR FROM "ExpiryDate") = 2012 ...
If you have index on ExpiryDate column - it's better to avoid using functions and have exact date/timestamp range:
and "ExpiryDate">='2012-01-01' and "ExpiryDate"<'2013-01-01';

SQL to Return Dates for Selected Week Only

I'm writing a SQL query on a timesheet report. I need the report to return only the details for the week of the selected date.
E.g., if I pick 02/01/2012 (dd/MM/yyyy), then it should only return results between 02/01/2012 and 08/01/2012.
Thanks
SELECT
*
FROM
yourTable
WHERE
dateField >= #yourDate
AND dateField < #yourDate + 7
Some variations of SQL may have specific ways of adding 7 days to a datevalue. Such as...
- DateAdd(Day, 7, #date)
- DATE_ADD(#date, INTERVAL 7 DAYS)
- etc, etc
This option is both index friendly, and is resilient to database fields that have time parts as well as date parts.
You easiest is the equivalent of WEEK_OF_YEAR function in your SQL engine
But you can also use DATE_ADD
WHERE table.date BETWEEN target_date AND DATE_ADD(target_date,INTERVAL 7 DAY)
That depends on the database system you're using. MySQL has a function calles WEEK(), SQL Server can do something like this with the DATEPART() function:
MySQL:
SELECT
*
FROM table
WHERE WEEK(date_col) = WEEK('02/01/2012');
SQL SERVER:
SELECT
*
FROM table
WHERE DATEPART(WEEK, datecol) = DATEPART(WEEK,'02/01/2012');
SELECT * FROM table_name
WHERE date BETWEEN '1/02/2012' AND '1/08/2012';
you can replace the example date with your date and yourdate + 6.
Look here for example: http://www.roseindia.net/sql/sql-between-datetime.shtml

How to get one day ahead of a given date?

Suppose I have a date 2010-07-29. Now I would like to check the result of one day ahead. how to do that
For example,
SELECT *
from table
where date = date("2010-07-29")
How to do one day before without changing the string "2010-07-29"?
I searched and get some suggestion from web and I tried
SELECT *
from table
where date = (date("2010-07-29") - 1 Day)
but failed.
MySQL
SELECT *
FROM TABLE t
WHERE t.date BETWEEN DATE_SUB('2010-07-29', INTERVAL 1 DAY)
AND '2010-07-29'
Change DATE_SUB to DATE_ADD if you want to add a day (and reverse the BETWEEN parameters).
SQL Server
SELECT *
FROM TABLE t
WHERE t.date BETWEEN DATEADD(dd, -1, '2010-07-29')
AND '2010-07-29'
Oracle
SELECT *
FROM TABLE t
WHERE t.date BETWEEN TO_DATE('2010-07-29', 'YYYY-MM-DD') - 1
AND TO_DATE('2010-07-29', 'YYYY-MM-DD')
I used BETWEEN because the date column is likely DATETIME (on MySQL & SQL Server, vs DATE on Oracle), which includes the time portion so equals means the value has to equal exactly. These queries give you the span of a day.
If you're using Oracle, you can use the + and - operators to add a number of days to a date.
http://psoug.org/reference/date_func.html
Example:
SELECT SYSDATE + 1 FROM dual;
Will yield tomorrow's date.
If you're not using Oracle, please tell use what you ARE using so we can give better answers. This sort of thing depends on the database you are using. It will NOT be the same across different databases.
Depends of the DateTime Functions available on the RDBMS
For Mysql you can try:
mysql> SELECT DATE_ADD('1997-12-31',
-> INTERVAL 1 DAY);
mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY);
-> '1997-12-02'
If youre using MSSQL, you're looking for DateAdd() I'm a little fuzzy on the syntax, but its something like:
Select * //not really, call out your columns
From [table]
Where date = DateAdd(dd, -1, "2010-07-29",)
Edit: This syntax should be correct: it has been updated in response to a comment.
I may have the specific parameters in the wrong order, but that should get you there.
In PL SQL : select sysdate+1 from dual;

To get date from datetime in sql

I have datecreated field in a table. It contains value as "2009-12-30 11:47:20:297"
I have a query like this:
select *
from table
where DateCreated = getdate()
Although one row exists with today's date, I am not getting that row while executing above query. Can anybody help?
The reason why your query doesn't return the row you expect, is because GETDATE() returns the date and time portion at the moment the query was executed. The value in your DateCreated column will not match the time portion, so no rows are returned.
There are various ways to construct a query so that it evaluates the date based on only the date component. Here's one example:
WHERE YEAR(datecreated) = YEAR(GETDATE())
AND MONTH(datecreated) = MONTH(GETDATE())
AND DAY(datecreated) = DAY(GETDATE())
The unfortunate reality is that any query using a function on the column means that if an index exists on the column, it can't be used.
You can use something like this with Sql Server
CREATE FUNCTION [dbo].[udf_DateOnly](#DateTime DATETIME)
RETURNS DATETIME
AS
BEGIN
RETURN DATEADD(dd,0, DATEDIFF(dd,0,#DateTime))
END
This line
DATEADD(dd,0, DATEDIFF(dd,0,#DateTime))
will strip out the Date portion.
The datetime field includes both the date and the time, accurate to the millisecond. Your query will only work if it is the exact millisecond stored in the database.
To check if it is today, but ignore the time of day, you can check for a range like this:
select * from table where
DateCreated >= '2009-12-30' and
DateCreated < '2009-12-31'
You can use that in conjunction with a function that converts the current date, as astander or Khilon has posted. Here is a full example using astander's answer. Also, as Craig Young points out, this will work with indexes.
select * from table where
DateCreated >= DATEDIFF(dd,0,GETDATE()) and
DateCreated < DATEDIFF(dd,0,GETDATE())
The simplest solution might be :
SELECT CAST(GETDATE() as DATE)
You can convert datetime to a string with only the date by using
CONVERT(varchar(8), GETDATE(), 112)
If needed, you can then change it back to datetime and as a result you'll get a datetime with the hours, minutes, seconds and milliseconds set to zero.