Adventures in Machine Learning

Converting Data Made Easy with SQL Server’s TRY_PARSE() Function

SQL Server TRY_PARSE() Function: A Powerful Tool for Data Conversion

Data conversion is a crucial aspect of working with databases, and SQL Server provides a variety of functions to facilitate it. One of the most interesting and powerful of these functions is TRY_PARSE().

TRY_PARSE() is a conversion function that attempts to convert an input expression to the specified data type, using the specified culture. In this article, we will explore the syntax and parameters of TRY_PARSE(), as well as provide some examples of how it can be used to convert strings to date/time and number, and how it can be used with a CASE expression.

Syntax of TRY_PARSE() Function

The syntax of the TRY_PARSE() function is straightforward and easy to understand. It takes three parameters: an expression that you want to convert, the data type to which you want to convert it, and the culture that the input string is being converted from.

The general syntax for TRY_PARSE() is as follows:

TRY_PARSE(expression AS data_type [ USING culture ])

Parameters of TRY_PARSE() Function

The TRY_PARSE() function takes three parameters: expression, data_type, and culture.

  1. Expression

    This is the expression that you want to convert. It can be a string, a number, a date/time value, or any other type of value that can be converted to the specified data type.

  2. Data_type

    The data type to which you want to convert the expression.

    The data types that are supported by TRY_PARSE() include date/time, numeric, and string data types.

  3. Culture

    The culture that the input string is being converted from. The culture parameter is optional, and if you don’t specify it, SQL Server will use the default culture of the server.

Examples of Using SQL Server TRY_PARSE() Function

Here are some examples that demonstrate the use of TRY_PARSE() function in SQL Server.

Example 1: Converting a string to date/time

One of the most common use cases for TRY_PARSE() is to convert a string to date/time.

Here’s an example of how you can use TRY_PARSE() to convert a string to date/time.

SELECT TRY_PARSE('2022-01-02 10:20:30' AS datetime)

The output of this query will be: 2022-01-02 10:20:30.000

Example 2: Converting a string to number

Another common use case for TRY_PARSE() is to convert a string to a number.

Here’s an example of how you can use TRY_PARSE() to convert a string to a number.

SELECT TRY_PARSE('123.45' AS numeric(10,2))

The output of this query will be: 123.45

Example 3: Using TRY_PARSE() function with CASE expression

TRY_PARSE() is often used in conjunction with a CASE expression to handle cases where the conversion might fail.

Here’s an example of how you can use TRY_PARSE() with a CASE expression to handle cast succeeded/failed cases.

SELECT column1,
       CASE WHEN TRY_PARSE(column2 as int) IS NULL THEN 'N/A'
            ELSE TRY_PARSE(column2 AS int) END as column2_int

FROM mytable

In this example, if the conversion of column2 to int fails, the CASE expression returns ‘N/A’.

Final Thoughts

TRY_PARSE() is a powerful function that can be used to convert data between different data types. Its ability to convert strings to date/time and numbers makes it a valuable addition to any database professional’s toolkit.

We hope this article has provided you with a brief overview of the syntax and parameters of TRY_PARSE(), as well as some practical examples of how it can be used in SQL Server.

Popular Posts