Try_cast Function in SQL Server: Tips and Examples

Try_cast Function in SQL Server is easier to understand when the core ideas are paired with practical examples. The sections below explain the topic clearly, highlight useful steps, and point out details that can prevent common errors.

This guide will show you in detail how to use the TRY_CAST data type conversion function in SQL Server with specific syntax and examples to better visualize and capture functions.

Describe

The TRY_CAST function in SQL Server converts an expression from one data type to another. If the conversion fails, TRY_CAST will return NULL, otherwise it will return the corresponding conversion value.

Syntax

To use TRY_CAST function in SQL Server, we use the following syntax:

 TRY_CAST(bieuthuc AS kieudulieu [(do_dai)])

Parameters :

bieuthuc: value to convert to another data type, can also be the name of a column in the table or a calculation expression that needs to be converted to a new data type.
kieudulieu: the new data type name to which the expression will be converted. Probably 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.
TRY_CAST can be used in later versions of SQL Server: SQL Server 2017, SQL Server 2016, SQL Server 2014, SQL Server 2012.

As an example,

Take a look and explore some examples of TRY_CAST functions in SQL Server.

 SELECT TRY_CAST(14.85 AS int); 
 Result: 14 
 (k?t qu? l� m?t gi� tr? int b? c?t ph?n th?p ph�n) 
 
 SELECT TRY_CAST(14.85 AS float); 
 Result: 14.85 
 (k?t qu? ???c tr? v? d??i d?ng gi� tr? float v� kh�ng b? c?t ng?n) 
 
 SELECT TRY_CAST('14 Main St.' AS float); 
 Result: NULL 
 (k?t qu? l� NULL v� kh�ng th? chuy?n ??i gi� tr? chu?i n�y th�nh float) 
 
 SELECT TRY_CAST(15.6 AS varchar); 
 Result: '15.6' 
 (k?t qu? ???c tr? v? d??i d?ng varchar) 
 
 SELECT TRY_CAST(15.6 AS varchar(2)); 
 Result: NULL 
 (k?t qu? l� NULL v� chuy?n ??i kh�ng th�nh c�ng do gi� tr? kh�ng ph� h?p v?i 
 varchar ?? d�i 2 k� t?) 
 
 SELECT TRY_CAST('2018-09-13' AS datetime); 
 Result: '2018-09-13 00:00:00.000' 
 (k?t qu? ???c tr? v? d??i d?ng datetime)

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FAQ

What should you know about describe?

The TRY_CAST function in SQL Server converts an expression from one data type to another. If the conversion fails, TRY_CAST will return NULL, otherwise it will return the corresponding conversion value.