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This SQL Server tutorial explains how to use the TRY_CONVERT function in SQL Server (Transact-SQL) with syntax and examples.

Description

In SQL Server (Transact-SQL), the TRY_CONVERT function tries to convert an expression from one datatype to another datatype. If the conversion fails, the function will return NULL. Otherwise, it will return the converted value.

Syntax

The syntax for the TRY_CONVERT function in SQL Server (Transact-SQL) is:

TRY_CONVERT( type [ (length) ], expression [ , style ] )

Parameters or Arguments

type

The datatype that you wish to convert expression to. It can be one of the following: bigint, int, smallint, tinyint, bit, decimal, numeric, money, smallmoney, float, real, datetime, smalldatetime, char, varchar, text, nchar, nvarchar, ntext, binary, varbinary, or image.

length

Optional. The length of the resulting data type for char, varchar, nchar, nvarchar, binary and varbinary.

expression

The value to convert to another datatype.

style

Optional. The format used to convert between datatypes, such as a date format or string format. It can be one of the following values:

Converting datetime to character

Converting float to real

Converting money to character

Note

• When casting from a float or numeric to an integer, the TRY_CONVERT function will truncate the result. For other conversions, the TRY_CONVERT function will round the result.
• See also the CONVERT, CAST, and TRY_CAST functions.

Applies To

The TRY_CONVERT function can be used in the following versions of SQL Server (Transact-SQL):

• SQL Server 2017, SQL Server 2016, SQL Server 2014, SQL Server 2012

Example

Let’s look at some SQL Server TRY_CONVERT function examples and explore how to use the TRY_CONVERT function in SQL Server (Transact-SQL).

For example:

SELECT TRY_CONVERT(int, 14.85);
Result: 14
(result is a truncated int value)

SELECT TRY_CONVERT(float, 14.85);
Result: 14.85
(result is returned as a float value and is not truncated)

SELECT TRY_CONVERT(float, '14 Main St.');
Result: NULL
(result is NULL because conversion failed since this string value can not be converted to a float)

SELECT TRY_CONVERT(varchar, 15.6);
Result: '15.6'
(result is returned as a varchar)

SELECT TRY_CONVERT(varchar(2), 15.6); 
Result: NULL
(result is NULL because conversion failed since the value will not fit in a 2 character varchar)

SELECT TRY_CONVERT(datetime, '2018-09-13');
Result: '2018-09-13 00:00:00.000'
(result is returned as a datetime)

SELECT TRY_CONVERT(varchar, '2018-09-13', 101);
Result: '09/13/2018'
(result is returned as a varchar with a style of 101 - mm/dd/yyyy (US standard) )