Как вытащить дату из datetime sql

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MS SQL Server — How to get Date only from the datetime value?

September 1, 2018

To get the current date and time:

And we have a datetime value: 2018-09-01 11:50:05.627

From the datetime value above, you want to extract the date value only and hide the time value. There are several ways to do that:

1. Use CONVERT to VARCHAR:

In this case, date only, you we are gonna run this query:

It returns 2018/09/01 for my test.

The style we used just now is 111, which is yyyy/mm/dd. There are many other style you can choose from. Here are some common types:

Because each type generates a different length, so you should define the right varchar length then.

2. You can also convert to date:

It will return the current date value along with starting value for time. For example, the result for my case is:

For older version than SQL Server 2008, you should use this instead:

And it returns the same result.

3. Use CAST

For the example above, you can use:

Or you can cast it to varchar:

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Как вытащить дату из datetime sql

In MS SQL Server, dates are complicated for newbies, since while working with the database, the format of the date in the table must be matched with the input date in order to insert. In various scenarios instead of date, DateTime (time is also involved with date) is used. In this article, we will learn how to convert a DateTime to a DATE by using the three different functions.

The aim of this article data is to convert DateTime to Date in SQL Server like YYYY-MM-DD HH:MM: SS to YYYY-MM-DD.

Method 1: Using cast

This is a function for casting one type to another type, So here we will use for cast DateTime to date.

Syntax:

Example 1:

Query:

Output:

GETDATE(): This function return current date time like(2021-08-27 17:26:36.710)

Example 2;

Query:

Output:

Method 2: Using Convert

This is a function for convert one type to another type, So here we will use it to convert DateTime to date.

Syntax:

Example 1:

Query:

Output:

Example 2:

Query:

Output:

Method 3: Try_Convert

This is a function for casting one type to another type, So here we will use for Convert DateTime to date. if the date is invalid then it will be null while Convert generates an error.

Syntax:

SELECT TRY_CONVERT(DATE,’2021-08-27 17:26:36.710′) AS CURRENT_DATE_GFG

Example 1:

Query:

Output:

Example 2:

Query:

Output:

Method 4: Using Substring

This is a function to use get a short string or substring, so here use we get substring 0 to 11 index.

Convert ‘datetime’ to ‘date’ in SQL Server (T-SQL Examples)

This article contains examples of converting a datetime value to a date value in SQL Server.

The obvious consequence of converting a datetime value to date is that you lose the time portion. However, one benefit is that you reduce the storage size from 8 bytes down to 3 bytes. Either way, you would only do this conversion if you don’t need the time portion.

The datetime data type includes the date and time, with a 3 digit fractional seconds part. Its accuracy is rounded to increments of .000, .003, or .007 seconds.

However, the date data type has an accuracy of 1 day (and it doesn’t include the time, as mentioned).

Example 1 – Implicit Conversion

Here’s an example of an implicit conversion between datetime and date.

This is an implicit conversion because we’re not using a conversion function (like the ones below) to explicitly convert it. In this case, SQL Server performs an implicit conversion behind the scenes when we try to assign the datetime value to a date variable.

In this example we can see that the date value only includes the date (without the time component).

Example 2 – Explicit Conversion using CAST()

Here’s an example of an explicit conversion. In this case, I use the CAST() function directly within the SELECT statement to explicitly convert between datetime and date.

Example 3 – Explicit Conversion using CONVERT()

Here’s an example of an explicit conversion using the CONVERT() function instead of CAST() .

How to get Date Part only from DateTime in Sql Server

Many times we come across a scenario where we need to get Date Part only from DateTime in Sql Server. There are multiple ways of doing this, here I am listing out few of them:

1) Below approach works in Sql Server 2008 and above:

2) Below approaches works in all the versions of Sql server

i) Get Date Part only from DateTime using CONVERT function
Example 1:

The results of the above query is of type VARCHAR, if we want the result to be of type DATETIME we can write a query like below:

ii) Get Date Part only from DateTime using DateTime functions

From performance perspective this is the better approach instead of first converting DATETIME to VARCHAR and then VARCHAR to DATETIME.

iii) Get Date Part only from DateTime using FLOOR and CAST functions

As we know Sql Server internally stores DATETIME as two 4-byte integers. First 4-byte stores the elapsed number days since SQL Server’s DATETIME type’s start date 19000101.The Second 4-bytes Store the Time of Day i.e. clock-ticks since midnight. Each clock-tick is equivalent to 3.33 milliseconds.

So with above said internal storgae of the DATETIME, we can first convert the DATETIME to DECIMAL, then from decimal part ignore the fractional position and get only the integer part. Finally convert the integer to DATETIME as shown below:

iv) Get Date Part only from DateTime using DATEPART and CONVERT functions