CAST vs CONVERT Function: Difference and Comparison

CAST and CONVERT are functions that convert one data type to another. The CAST function is a part of ANSI – SQL specifications, so it is more apt to be used than the CONVERT function.

This function is used to reduce or remove format while still converting.

Key Takeaways

  1. CAST is a function in SQL that allows for explicitly converting a data type into another using a standard syntax defined by ANSI SQL.
  2. CONVERT is a similar function to CAST but uses a more flexible, database-specific syntax, which may vary between different database systems.
  3. Both CAST and CONVERT functions are used in SQL to change data types, but they differ in their syntax, with CAST using a standardized syntax and CONVERT allowing for more database-specific variations.

CAST vs CONVERT Function

The difference between CAST and CONVERT is that CAST is an ANSI standard function that is portable to various database platforms; conversely, CONVERT is a function specific to SQL servers. There is also a significant difference in their syntax, as shown above.

Cast vs Convert function 1

Also, the CONVERT function can stimulate set date format options here, while the CAST function cannot perform such actions. A cast function can convert the data type without any specific format.

CAST function has an advantage over the CONVERT function that can never be overlooked; it is a portable function which in the general sense means that many database platforms can use it.

Unlike the other functions, this function is less powerful and less flexible. The syntax of this function is very simple, as follows:

CAST(expression AS type [ (length) ]): here expression refers to the value that you want to convert, type refers to the data type into which you want to do the conversion,

and length is an optional term. It is the resulting data type length for char, varchar, binary and varbinary.

On the other hand CONVERT function is a specific function for the SQL server. This function can also be used to convert one data type to another.

This function can be used for formatting purposes for date/time and money data types. Also, the CONVERT function can stimulate set date format options here, while the CAST function cannot perform such actions.

CONVERT function is a highly flexible function and a highly preferred function to use for date/time values. The earlier CAST function takes three parameters (length is optional). This function takes four parameters (length and style are optional).

The syntax of this function is slightly different and just a hint a bit longer than the CAST function and is the following:

CONVERT ( type [ (length) ], expression [, style] ): here, the expression refers to the value that you want to convert and refers to the data type into which you want to do the conversion. Length is an optional term. It is the resulting data type length for char, varchar, binary and varbinary. Style is another option used to convert between data types, such as date or string format.


 

Comparison Table

Parameter of ComparisonCAST FunctionCONVERT Function
TypeANSI standardSpecific to SQL
FlexibilityLess flexibleMore flexible
FunctionConvert data without a specific formatPerform converting and formatting at the same time
TaskIt preserves values while convertingI cannot do such a task
SyntaxCAST (expression AS type [ (length) ] )CONVERT ( type [ (length) ], expression [, style] )

 

What is CAST Function?

The CAST function is a part of ANSI – SQL specifications, which is why it is more apt to be used than the CONVERT function. This function is used to reduce or remove format while still converting.

CAST function has an advantage over the CONVERT function that can never be overlooked; it is a portable function which in the general sense means that many database platforms can use it.

This function still, unlike the other functions is less powerful and less flexible. The syntax of this function is very simple as the following:

CAST(expression AS type [ (length) ]): here, the expression refers to the value that you want to convert, type refers to the data type into which you want to do the conversion, and length is an optional term. It is the resulting data type length for char, varchar, binary and varbinary.

For example, CAST( 12.22 AS int)  Result will be 12.

 

What is CONVERT Function?

The CONVERT function is a specific function for the SQL server. This function can also be used to convert one data type to another.

This function can be used for formatting purposes for date/time and money data types. Also, the CONVERT function can stimulate set date format options here, while the CAST function cannot perform such actions.

The syntax of this function is slightly different and just a hint bit lengthy (only if you use optional) than the CAST function and is following:

CONVERT ( type [ (length) ], expression [, style] ): here, the expression refers to the value that you want to convert and refers to the data type into which you want to do the conversion. Length is an optional term. It is the resulting data type length for char, varchar, binary and varbinary. Style is another option used to convert between data types, such as date or string format.

For example:  CONVERT( 12.22 , int))  The result will be 12.

Main Differences Between CAST and CONVERT Functions

  1. CAST is an ANSI standard function that is portable to various database platforms; conversely, CONVERT is a function specific to SQL servers.
  2. CAST is a portable function used by various database platforms, but CONVERT is specific to SQL Server.
  3. The difference in syntax can also be observed above
  4. CAST is a less flexible function than the CONVERT function
  5. CONVERT is also used for formatting and converting simultaneously, but CAST cannot be used.

Last Updated : 11 June, 2023

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10 thoughts on “CAST vs CONVERT Function: Difference and Comparison”

  1. It’s reassuring to have a clear understanding of the differences and capabilities of CAST and CONVERT functions. Thanks for the detailed comparison.

    Reply
  2. Interesting article, very informative and well-explained. I appreciate the comparison and detailed explanation of both CAST and CONVERT functions.

    Reply
  3. The thorough explanation of the syntax and differences between CAST and CONVERT is valuable for SQL developers. Understanding when to use each function is essential.

    Reply
  4. The article provides a clear and detailed comparison of CAST and CONVERT functions, making it easier to understand their applications and syntax.

    Reply
  5. This kind of information is crucial for database developers. It’s great to know the differences between CAST and CONVERT and when to use each one.

    Reply
  6. This article effectively highlights the differences between CAST and CONVERT functions, and the comparison table is particularly informative and useful for SQL developers.

    Reply
  7. The detailed overview of both CAST and CONVERT functions provides a comprehensive understanding of the syntax and differences. It’s a valuable resource for SQL developers.

    Reply
  8. I didn’t realize the nuances between CAST and CONVERT functions. This article has provided a clear and concise comparison that enhances my knowledge.

    Reply
  9. I appreciate the in-depth explanation of the CAST and CONVERT functions, and the comparison table is very helpful in understanding the differences.

    Reply
  10. The examples provided for both CAST and CONVERT functions really help in understanding their syntax and application. Useful information for SQL developers.

    Reply

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