This article explores the SQL Server PRINT statements, and its alternative SQL Server RAISEERROR statements to print
messages in a query.
Introduction
Suppose you execute a query with multiple steps. We want to get a message once each step completes. It helps to track the query progress. Usually, we use the SQL PRINT statement to print corresponding messages or track the variable values while query progress.
We also use interactions or multiple loops in a query with a while or for a loop. We can also use the SQL PRINT
statement to track the iteration.
We use the SQL Server PRINT statement to return messages to the client. We specify the message as string expressions input. SQL Server returns the message to the application.
In this article, we will explore several use cases of SQL PRINT statement, its limitations, and alternatives of SQL
PRINT statements.
Example 1: SQL Server PRINT statement to print a string
It is the simplest example. Execute the following query in SSMS, and it returns the following message in the output:
In SSMS, we get the PRINT statement output in SSMS message window as shown in the above image.
Example 2: PRINT statement to print a variable value
We can use the SQL PRINT statement to print a variable value as well. Let’s define a message in a variable and later
print this message:
We can specify only CHAR, NCHAR, VARCHAR or NVARCHAR data types in the PRINT statement. In this case, it implicitly converts an integer value to the VARCHAR data type internally.
Let’s use another example with an integer variable and a string in the PRINT statement. You get an error message in
data type conversion because SQL Server is trying to convert the varchar data type to integer. In data type
precedence, the integer data type has high precedence than the varchar data type:
We can use the SQL CONCAT function as well, and it automatically does data type conversion for us. In the following
query, we get the output using the CONCAT function similar to the CAST operator:
Example 4: SQL Server PRINT statement with XML type variable value
We can use XML data type as well with the PRINT statement, but it requires data conversion.
As shown in the following output, we cannot directly use an XML variable in the PRINT statement. It gives an error
message that implicit conversion from XML to nvarchar is not allowed:
Example 5: SQL Server PRINT Statement with IF conditions
Let’s use the PRINT statement to print the message satisfied in the IF condition. In this example, the variable @a
contains a string. The IF condition checks for the string and prints message satisfying the condition:
Let’s use the following query that contains a variable with NULL values. In the PRINT statement, we use a string
along with this variable, and it does not return any message. The concatenation of a string and the variable @a
(NULL) that does not return any output:
Example 7: SQL Server PRINT Statement in a WHILE loop
As stated earlier, many times, we require knowing information about each iteration when query running in a loop such as WHILE or FOR.
The following query uses WHILE loop and prints a message about each iteration:
Limitations of SQL Server PRINT statement
In the previous example, we saw the use of cases of SQL PRINT statements. We have the following limitations with
PRINT as well:
We need to use CAST, CONVERT or CONCAT functions in the PRINT statement with variables
We cannot see a PRINT statement in SQL PROFILER
The PRINT statement does not return the message immediately; it buffers the output and displays them
Let’s elaborate point no 3 and see its alternatives.
Execute the following query that contains two PRINT statements. Looking at the query, you might think of output in
the following form:
It gives the message from the first PRINT statement
Waits for 5 seconds
It gives the message for a second PRINT statement
Waits for another 5 seconds
In the following GIF image, you can note that it prints message from both SQL PRINT statements together after 10
seconds:
Let’s use another example and see PRINT statement behavior. In this, we want to print the message as soon as
iteration completes:
In the output, we can note that all messages output from PRINT statements appear together once the execution
completes. The loop executes 14 times and waits 1 second on each execution. Therefore, we get output after 14
seconds for all PRINT statements:
It is not the desired output, and in any case, it might not be useful as you cannot track query progress in
real-time.
SQL Server RAISERROR statement
We can use an alternative to the SQL PRINT statement that is RAISERROR.
We require a few arguments in RAISERROR statements.
Message
– It is the message that we want to print
Severity
– It is a number between 0 and 25 and defines the severity of the messages. It treats
the message differently with each severity. We will see a few examples of it in this article
State
– It is a number between 0 and 255 to distinguish one error from another. It is good to
use value 1 for this article
We need to use RAISERROR statement with NOWAIT clause; otherwise, it shows the same behavior as of SQL PRINT
statement:
Let’s execute the following query with severity 1 and severity 16. Severity 1 shows the message with additional information, but it does not show the message as an error. You can see the text color in black.
Another SQL Server RAISERROR shows the output message as an error:
We cannot use SQL Server RAISERROR directly using the variables. We get the following output that is not the desired
output:
We need to use the C-style print statements with RAISERROR. The following query shows the variable with the
RAISERROR. You can notice that we use %s and %d to print a string and integer value:
We get the instant output in SQL Server RAISERROR along with WITH NOWAIT statement as per our requirement and does
not use buffer to display output once the query finishes:
You might confuse between RAISERROR statement that it is for raising error messages in SQL Server. We can use it as an alternative to the SQL PRINT statement as well. Usually, developers use PRINT statements only to gives messages in a query. You should explore RAISERROR statements for your queries, stored procedures.
Conclusion
In this article, we explored the SQL Server PRINT statement and its usages to track useful milestones in a query. We also learned the limitations of it along with alternative solution RAISERROR statement in SQL Server. SQL Server
RAISERROR gives you a great advantage to control output buffer behavior.
Hi! I am Rajendra Gupta, Database Specialist and Architect, helping organizations implement Microsoft SQL Server, Azure, Couchbase, AWS solutions fast and efficiently, fix related issues, and Performance Tuning with over 14 years of experience.
I am the creator of one of the biggest free online collections of articles on a single topic, with his 50-part series on SQL Server
Always On Availability Groups
.
Based on my contribution to the SQL Server community, I have been recognized as the prestigious
Best Author of the Year
continuously in 2019, 2020, and 2021 (2nd Rank) at SQLShack and the MSSQLTIPS champions award in 2020.
Hi! I am Rajendra Gupta, Database Specialist and Architect, helping organizations implement Microsoft SQL Server, Azure, Couchbase, AWS solutions fast and efficiently, fix related issues, and Performance Tuning with over 14 years of experience.
I am the author of the book "
DP-300 Administering Relational Database on Microsoft Azure
". I published more than 650 technical articles on MSSQLTips, SQLShack, Quest, CodingSight, and SeveralNines.
I am the creator of one of the biggest free online collections of articles on a single topic, with his 50-part series on SQL Server
Always On Availability Groups
.
Based on my contribution to the SQL Server community, I have been recognized as the prestigious
Best Author of the Year
continuously in 2019, 2020, and 2021 (2nd Rank) at SQLShack and the MSSQLTIPS champions award in 2020.
Personal Blog:
https://www.dbblogger.com
I am always interested in new challenges so if you need consulting help, reach me at
[email protected]
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