Difference Between UDF and Stored Procedure in SQL (With Table)

Today’s world demands us to be equipped with the ability to understand and use computers with ease. If we ponder upon it, we will realize that learning about it will do us good than harm. It is where the future lies, after all. To get into the nuances of this virtual world, we should familiarize ourselves with UDF and Stored Procedures in SQL.

UDF vs Stored Procedure in SQL

The difference between UDF and Stored Procedure is that while the former typically generates a return value and it should be a part of the SQL statement for it to be executed, the latter does not always generate a return value, it is optional, and it can return zero apart from other values as well.

UDF is the acronym for User Defined Functions. The name makes it abundantly clear that in this feature, the users can define their functions. Not only can one create the functions, but he can modify them as well. Furthermore, it typically generates a return value, and it should be a part of the SQL statement for it to be executed.

On the other hand, Stored Procedure is also stored in the database, but it still differs from the above-discussed. The procedures here cannot be called from the UDF, and it has either input parameters or output. Furthermore, it does not always generate a return value, it is optional, and it can return zero apart from other values.

Comparison Table Between UDF and Stored Procedure in SQL

Parameters of ComparisonUDF in SQL Stored Procedure in SQL
Return ValueIt typically generates a return valueIt does not always generate a return value; it is optional and can return zero apart from other values
Execution
It can be executed only if it is a part of an SQL statementIt can be executed by a command “EXECUTE”
ParametersIt only has input parametersIt has either input parameter or output
AlterationsThey receive data as parameters and they cannot be changed or rather aren’t allowed to be changedThey can alter database objects
JOINsIt can be used in JOINsOutput cannot JOIN

What is UDF in SQL?

UDF is the acronym for User Defined Functions. The name makes it abundantly clear that in this feature, the users can define their functions. Not only can one create the functions, but he can modify them as well. In other words, the user can define his functions by employing the “CREATE FUNCTION” option. These functions can be referenced in Transact-SQL alone by using syntax that is defined in the Transact-SQL Reference. Furthermore, it typically generates a return value, and it should be a part of the SQL statement for it to be executed.

It is pertinent to note that it offers its users a variety of features. All the functions here can be called from the Procedure. It only has input parameters and is devoid of the output parameters. They receive data as parameters, and they cannot be changed or, rather, aren’t allowed to be changed. They can be used in set operations and can also be used in JOINs. It can be used anywhere in the SQL statements.

There is more to add to the list. The functions support just a SELECT statement and also allows a SELECT statement. It does not support “try-catch”. It can use the data types that an SQL server supports. However, it does not support transaction management.

What is Stored Procedure in SQL?

It is also stored in the database, but it still differs from the above-discussed. This is nothing but the SQL code that is prepared by one for repeated usage. Instead of having to rewrite the same query over and over again each time we need it, this offers us the simple and valuable option of simply storing it as a “Stored Procedure”. The procedures here cannot be called from the UDF, and it has either input parameters or output. Furthermore, it does not always generate a return value, it is optional, and it can return zero apart from other values.

It provides numerous features. We know that this offers us the privilege of simply storing queries that we know will come in handy more than once. In addition to this, it can also pass parameters to the procedure that is stored. Based on such parameters that were passed, the stored procedure act accordingly.

They improve the performance as the stored procedures are used repeatedly. It also has either input parameters or output parameters. The data that they receive can easily be changed. For people who live in bad network coverage areas, this can be very helpful as it can reduce lengthy queries to a single line and then transmits it over the wire.

Main Differences Between UDF and Stored Procedure in SQL

  1. While UDF is the acronym for User Defined Functions, and the name makes it abundantly clear that in this feature, the users can define their functions, Stored Procedure is nothing but the SQL code that is prepared by one for repeated usage.
  2. While UDF features only input parameters, Stored Procedure features either the input parameter or the output parameter.
  3. UDF does not permit the usage of the “Try-catch” blocks. On the other hand, Stored Procedure allows the usage of the “Try-catch” block.
  4. The functions on the UDF are called from the Procedures. However, In the case of Stored Procedures, Procedures are not or rather cannot be called from the UDF.
  5.  In the case of UDF, for the functions to be executed, they have to be a part of an SQL statement. In contrast, the functions in Stored Procedure can be executed by a simple command, that is, “EXECUTE”.

Conclusion

It has become next to impossible to function at a professional or even at a personal level without the knowledge of computers. But for those whose jobs dictate them to have a stronghold over it, you must step up. One difference that becomes quite significant to be known is the difference between UDF and Stored Procedure.

While the former typically generates a return value, and it should be a part of the SQL statement for it to be executed, the latter does not always generate a return value, it is optional, and it can return zero apart from other values as well. UDF is the acronym for User Defined Functions. The name makes it abundantly clear that in this feature, the users can define their functions. Not only can one create the functions, but he can modify them as well. On the other hand, Stored Procedure is the SQL code that is prepared by one for repeated usage.

References

  1. https://dl.acm.org/doi/abs/10.1145/276305.276335
  2. https://en.cnki.com.cn/Article_en/CJFDTotal-DNZS201123012.htm
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