sql server datetime column get date only

SQL Server Datetime Column Get Date Only

When working with datetime columns in SQL Server, you may sometimes need to extract only the date part from the datetime value. This can be useful for various reasons, such as filtering records based on the date portion only or performing date-specific calculations. In this article, we will explore different ways to get the date only from a datetime column in SQL Server.

Using the CAST Function

One common approach to extract the date part from a datetime column is to use the CAST function with the DATE data type. The DATE data type represents only the date portion of a datetime value.

SELECT CAST(datetime_column AS DATE) AS date_only
FROM your_table_name;

In this query, replace datetime_column with the name of your datetime column and your_table_name with the name of your table. The CAST function converts the datetime value in the datetime_column to a DATE value, resulting in only the date portion being displayed in the date_only column.

Using the CONVERT Function

Another method to extract the date part from a datetime column is to use the CONVERT function with a style code that specifies the date format. In this case, the style code 112 is used to represent the yyyymmdd format.

SELECT CONVERT(VARCHAR(10), datetime_column, 112) AS date_only
FROM your_table_name;

In this query, the CONVERT function converts the datetime value in the datetime_column to a VARCHAR value with the yyyymmdd format, resulting in only the date portion being displayed in the date_only column.

Using the FORMAT Function (SQL Server 2012 and later)

If you are using SQL Server 2012 or later versions, you can also use the FORMAT function to extract the date part from a datetime column. The FORMAT function allows you to format datetime values in various ways, including displaying only the date portion.

SELECT FORMAT(datetime_column, 'yyyy-MM-dd') AS date_only
FROM your_table_name;

In this query, the FORMAT function formats the datetime value in the datetime_column to display only the date portion in the yyyy-MM-dd format. This approach provides more flexibility in formatting the date output compared to the CAST and CONVERT functions.

Conclusion

In this article, we have discussed different methods to extract the date part from a datetime column in SQL Server. Depending on your requirements and the SQL Server version you are using, you can choose the appropriate method to achieve the desired result. Whether you prefer using the CAST, CONVERT, or FORMAT function, it is important to consider the performance implications and the output format when extracting the date only from a datetime column.

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gantt
    title SQL Server Datetime Column Get Date Only
    section Extract Date from Datetime Column
    CAST: done, after query1, 2d
    CONVERT: done, after query2, 2d
    FORMAT: done, after query3, 2d

classDiagram
    Class01 <|-- SQLServerDatetime
    Class02 <|-- CASTFunction
    Class03 <|-- CONVERTFunction
    Class04 <|-- FORMATFunction

In the class diagram above, we can see the relationships between the different classes involved in extracting the date from a datetime column in SQL Server. The SQLServerDatetime class is the parent class, with CASTFunction, CONVERTFunction, and FORMATFunction as child classes representing the different methods discussed in the article.

By utilizing these methods, you can effectively extract the date portion from a datetime column in SQL Server for your data processing needs. Choose the method that best fits your requirements and consider the performance implications to optimize your SQL queries efficiently.