Тази статия ще ви научи на пълен преглед на използването на WHILE цикъла в SQL Server. А Цикълът WHILE е израз за контролен поток, използван за многократно изпълнение на набор от изрази, докато определеното условие бъде изпълнено . Този цикъл започва с дадено условие, оценете го и ако е TRUE, операторите ще влязат в цикъла за по-нататъшно изпълнение. Ако условието стане FALSE, то няма да се изпълни. Това предполага, че цикълът while в SQL Server може да се изпълнява нула или повече пъти.
Блок-схема на цикъл WHILE
Следващата блок-схема ще обясни пълния работен процес на WHILE цикъла в SQL Server:
python // оператор
Можем да видим в тази диаграма, че определеното условие се проверява за всяка итерация и въз основа на резултата от оценката се определя кодовият поток. Ако резултатът е оценен като TRUE, контролният поток преминава вътре в цикъла за по-нататъшно изпълнение. Ако оцененият резултат е FALSE, контролният поток ще излезе от цикъла и всеки израз или заявка извън цикъла ще бъде изпълнена.
Синтаксис
Следният синтаксис илюстрира WHILE цикъла в SQL Server:
WHILE boolean_condition BEGIN BREAK END;
В този синтаксис имаме следните параметри или аргументи:
Пример за цикъл WHILE
Нека разберем как работи цикълът WHILE в SQL Server чрез пример. В дадения пример първо сме декларирали стойност от целочислен тип и задайте стойността му на 1. След това цикълът WHILE проверява условието и дали е така ВЯРНО , изявлението за печат ще бъде отпечатано. Когато примката стане НЕВЯРНО , следващият оператор след цикъла WHILE ще бъде отпечатан.
DECLARE @stud_value INT; SET @stud_value = 1; WHILE @stud_value <= 5 begin print 'mark henry'; set @stud_value="@stud_value" + 1; end; 'rose bennet'; < pre> <p>Executing this statement will return the following output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-2.webp" alt="SQL Server WHILE LOOP"> <p>In the above WHILE loop code snippet, we must increment the variable's value after each iteration. See the below part of the above code line as <strong>SET @stud_value = @stud_value + 1</strong> . If we do not write this statement, the loop will execute infinitely because it cannot becomes FALSE.</p> <pre> BEGIN PRINT 'Mark Henry'; SET @stud_value = @stud_value + 1; END; </pre> <h3>Infinite WHILE Loop</h3> <p>An infinite loop occurs when the evaluation of a condition will never be false. Therefore, the loop will never end and be executed forever. The loop in the following code snippet is infinite because the variable's value is not incremented.</p> <pre> DECLARE @stud_value INT; SET @stud_value = 1; WHILE @stud_value <= 5 begin print 'please stop execution!' end; < pre> <p>Executing the loop will display the below output. This loop will never end its execution until we do not cancel their execution of the query manually.</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-3.webp" alt="SQL Server WHILE LOOP"> <h3>Inserting Records with WHILE Loop</h3> <p>We can also use the WHILE loop to insert records into the defined table. Let us see how to inserts dummy records into the database. First, we will create a table named <strong>'bikeshop'</strong> containing three columns: <strong>Id, bike_name,</strong> and <strong>price</strong> . Execute the following statement to create this table:</p> <pre> CREATE TABLE bikeshop ( Id INT PRIMARY KEY IDENTITY, bike_name VARCHAR (50) NOT NULL, price FLOAT ) </pre> <p>Next, we will use the WHILE loop to insert ten records into this table by executing the following script:</p> <pre> DECLARE @count INT; SET @count = 1; WHILE @count <= 10 begin insert into bikeshop values('bike-' + cast(@count as varchar), @count*5000) set @count="@count" 1; end; < pre> <p>In this code, we have declared a variable @ <strong>count</strong> and then initialize its value with 1 using a SET clause. Next, we have to define the loop body that executes the INSERT statement to add one record in each execution. The <strong>bike_name column</strong> will append the value of a @count variable with the string <strong>Bike</strong> , and the <strong>price</strong> column determines by the value of a @count variable multiplied by <strong>5000</strong> . The loop will execute until the value of the @count variable becomes FALSE. It means the WHILE loop will execute ten times and <strong>inserts ten records</strong> into the table bikeshop.</p> <p>Now, we can verify all the records of the bikeshop table with the SELECT statement. It will display the following output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-4.webp" alt="SQL Server WHILE LOOP"> <h3>BREAK Statement</h3> <p>SQL Server also allows us to use the BREAK statement in the WHILE loop like programming languages. This statement is used to <strong>immediately stop the current iteration of the loop</strong> , and control flow resumes with the next statement after the loop. In general, we will use the <a href="/sql-server-if-else"> <strong>IF...ELSE statement</strong> </a> to check whether or not a condition has occurred.</p> <p>The following example will explain how to use the BREAK statement in the WHILE loop:</p> <pre> DECLARE @count INT; SET @count = 1; WHILE @count = 6 BEGIN BREAK END SET @Count = @Count + 1 END; </pre> <p>Executing the code will display the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-5.webp" alt="SQL Server WHILE LOOP"> <p>The value of the variable is first evaluated in this code. If it is TRUE, the control enters into the loop and prints the statement. When the variable value is greater than or equal to 6, control enters the IF...ELSE block and executes the BREAK statement to terminate the loop. If an IF...ELSE block fails to meet the condition; then, the loop will keep running until the condition is changed to FALSE.</p> <h3>CONTINUE Statement</h3> <p>SQL Server also allows us to use the CONTINUE statement in the WHILE loop like programming languages. This statement immediately <strong>terminates the current execution of the loop when the specified condition is met</strong> , and control flow returns to the beginning of the loop. In general, the IF...ELSE statement will be used to test whether or not a condition has been met.</p> <p>The CONTINUE statement in the WHILE loop is demonstrated in the following example. In this example, we'll assume that we wish to use a WHILE loop to <strong>print only odd values</strong> . The CONTINUE statement can be used to do this. This example will first <strong>test</strong> whether the variable value is <strong>odd or even</strong> . If it is even, the execution goes inside the IF…ELSE statement blocks and decrement the variable value by one. Then, it will execute the CONTINUE statement and starts a new iteration from the beginning.</p> <pre> DECLARE @Count INT SET @Count = 1 WHILE (@Count <= 1 2="0" 44 20) begin if @count % set + continue end print 'the odd value is=" + CONVERT(VARCHAR, @Count) SET @Count = @Count + 1 END </pre> <p>Executing the code snippet will display the below output:</p> <img src=" techcodeview.com img sql-server-tutorials sql-server-while-loop-6.webp' alt="SQL Server WHILE LOOP"> <h3>How to implementing paging with WHILE loop in SQL Server?</h3> <p>We can also use the WHILE loop for implementing the paging. Paging allows displaying the subset of records from a table at any particular time. The following example will explain this concept. The WHILE loop in the code will select two records from the bikeshop table at a time. The records that have been chosen are then displayed in the output.</p> <pre> DECLARE @count INT DECLARE @limit INT; SET @count = 0 SET @limit = 2; WHILE @count <10 begin select * from bikeshop order by id offset @count rows fetch next @limit only set + 2; end; < pre> <p>Executing the code snippet will return the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-7.webp" alt="SQL Server WHILE LOOP"> <h3>Nested WHILE Loop</h3> <p>The Nested WHILE Loop in SQL Server is simply a WHILE Loop written inside another WHILE Loop. When we work on multi-layered data, the Nested WHILE loops are essential. Because this concept is useful in extracting the layered data when we want to select them, it is recommended to be careful while using the nested loop.</p> <p> <strong>Syntax</strong> </p> <p>The following syntax illustrate the working of the nested WHILE Loop in SQL Server:</p> <pre> WHILE Expression BEGIN WHILE @Val2 <= 10 begin --second while loop statements sql end --this statement is outside the second --which first -- this < pre> <p>Let us explain this syntax step by step:</p> <p> <strong>Step 1:</strong> The loop starts by checking the first WHILE loop condition, and if it finds a false result, it will exit from While Loop. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution. This block will start the execution of the second WHILE loop. See step 2.</p> <p> <strong>Step 2:</strong> This step will check the condition in the Nested WHILE Loop, and if it is false, the second loop will be exit and execute the statement outside this. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution.</p> <p> <strong>Step 3:</strong> Once all the statements execute from the second WHILE loop, the control goes to the first WHILE and repeats the first step.</p> <p> <strong>Example</strong> </p> <p>The following example will print the multiplication table of 5 up to 10 using the nested WHILE loop.</p> <pre> DECLARE @val1 INT DECLARE @val2 INT SET @val1 = 5 SET @val2 = 1 WHILE @val1 <= 5 44 begin while @val2 <="10" print convert(varchar, @val1) + ' * @val2) techcodeview.com img sql-server-tutorials sql-server-while-loop-8.webp' alt="SQL Server WHILE LOOP"> <h2>Conclusion</h2> <p>The WHILE loop is a useful method when there is a need to execute a SQL script repeatedly. The article explained how to work with the WHILE loop in MS SQL Server to execute operations such as record insertion and pagination with a simple example. Here we have also learned the BREAK and CONTINUE statements to control the WHILE loop iteration.</p> <hr></=></pre></=></pre></10></pre></=></pre></=></pre></=></pre></=> Безкраен цикъл WHILE
Безкраен цикъл възниква, когато оценката на условие никога няма да бъде невярна. Следователно цикълът никога няма да свърши и ще бъде изпълнен завинаги. Цикълът в следния кодов фрагмент е безкраен, защото стойността на променливата не се увеличава.
DECLARE @stud_value INT; SET @stud_value = 1; WHILE @stud_value <= 5 begin print \'please stop execution!\' end; < pre> <p>Executing the loop will display the below output. This loop will never end its execution until we do not cancel their execution of the query manually.</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-3.webp" alt="SQL Server WHILE LOOP"> <h3>Inserting Records with WHILE Loop</h3> <p>We can also use the WHILE loop to insert records into the defined table. Let us see how to inserts dummy records into the database. First, we will create a table named <strong>'bikeshop'</strong> containing three columns: <strong>Id, bike_name,</strong> and <strong>price</strong> . Execute the following statement to create this table:</p> <pre> CREATE TABLE bikeshop ( Id INT PRIMARY KEY IDENTITY, bike_name VARCHAR (50) NOT NULL, price FLOAT ) </pre> <p>Next, we will use the WHILE loop to insert ten records into this table by executing the following script:</p> <pre> DECLARE @count INT; SET @count = 1; WHILE @count <= 10 begin insert into bikeshop values(\'bike-\' + cast(@count as varchar), @count*5000) set @count="@count" 1; end; < pre> <p>In this code, we have declared a variable @ <strong>count</strong> and then initialize its value with 1 using a SET clause. Next, we have to define the loop body that executes the INSERT statement to add one record in each execution. The <strong>bike_name column</strong> will append the value of a @count variable with the string <strong>Bike</strong> , and the <strong>price</strong> column determines by the value of a @count variable multiplied by <strong>5000</strong> . The loop will execute until the value of the @count variable becomes FALSE. It means the WHILE loop will execute ten times and <strong>inserts ten records</strong> into the table bikeshop.</p> <p>Now, we can verify all the records of the bikeshop table with the SELECT statement. It will display the following output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-4.webp" alt="SQL Server WHILE LOOP"> <h3>BREAK Statement</h3> <p>SQL Server also allows us to use the BREAK statement in the WHILE loop like programming languages. This statement is used to <strong>immediately stop the current iteration of the loop</strong> , and control flow resumes with the next statement after the loop. In general, we will use the <a href="/sql-server-if-else"> <strong>IF...ELSE statement</strong> </a> to check whether or not a condition has occurred.</p> <p>The following example will explain how to use the BREAK statement in the WHILE loop:</p> <pre> DECLARE @count INT; SET @count = 1; WHILE @count = 6 BEGIN BREAK END SET @Count = @Count + 1 END; </pre> <p>Executing the code will display the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-5.webp" alt="SQL Server WHILE LOOP"> <p>The value of the variable is first evaluated in this code. If it is TRUE, the control enters into the loop and prints the statement. When the variable value is greater than or equal to 6, control enters the IF...ELSE block and executes the BREAK statement to terminate the loop. If an IF...ELSE block fails to meet the condition; then, the loop will keep running until the condition is changed to FALSE.</p> <h3>CONTINUE Statement</h3> <p>SQL Server also allows us to use the CONTINUE statement in the WHILE loop like programming languages. This statement immediately <strong>terminates the current execution of the loop when the specified condition is met</strong> , and control flow returns to the beginning of the loop. In general, the IF...ELSE statement will be used to test whether or not a condition has been met.</p> <p>The CONTINUE statement in the WHILE loop is demonstrated in the following example. In this example, we'll assume that we wish to use a WHILE loop to <strong>print only odd values</strong> . The CONTINUE statement can be used to do this. This example will first <strong>test</strong> whether the variable value is <strong>odd or even</strong> . If it is even, the execution goes inside the IF…ELSE statement blocks and decrement the variable value by one. Then, it will execute the CONTINUE statement and starts a new iteration from the beginning.</p> <pre> DECLARE @Count INT SET @Count = 1 WHILE (@Count <= 1 2="0" 44 20) begin if @count % set + continue end print \'the odd value is=" + CONVERT(VARCHAR, @Count) SET @Count = @Count + 1 END </pre> <p>Executing the code snippet will display the below output:</p> <img src=" techcodeview.com img sql-server-tutorials sql-server-while-loop-6.webp\' alt="SQL Server WHILE LOOP"> <h3>How to implementing paging with WHILE loop in SQL Server?</h3> <p>We can also use the WHILE loop for implementing the paging. Paging allows displaying the subset of records from a table at any particular time. The following example will explain this concept. The WHILE loop in the code will select two records from the bikeshop table at a time. The records that have been chosen are then displayed in the output.</p> <pre> DECLARE @count INT DECLARE @limit INT; SET @count = 0 SET @limit = 2; WHILE @count <10 begin select * from bikeshop order by id offset @count rows fetch next @limit only set + 2; end; < pre> <p>Executing the code snippet will return the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-7.webp" alt="SQL Server WHILE LOOP"> <h3>Nested WHILE Loop</h3> <p>The Nested WHILE Loop in SQL Server is simply a WHILE Loop written inside another WHILE Loop. When we work on multi-layered data, the Nested WHILE loops are essential. Because this concept is useful in extracting the layered data when we want to select them, it is recommended to be careful while using the nested loop.</p> <p> <strong>Syntax</strong> </p> <p>The following syntax illustrate the working of the nested WHILE Loop in SQL Server:</p> <pre> WHILE Expression BEGIN WHILE @Val2 <= 10 begin --second while loop statements sql end --this statement is outside the second --which first -- this < pre> <p>Let us explain this syntax step by step:</p> <p> <strong>Step 1:</strong> The loop starts by checking the first WHILE loop condition, and if it finds a false result, it will exit from While Loop. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution. This block will start the execution of the second WHILE loop. See step 2.</p> <p> <strong>Step 2:</strong> This step will check the condition in the Nested WHILE Loop, and if it is false, the second loop will be exit and execute the statement outside this. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution.</p> <p> <strong>Step 3:</strong> Once all the statements execute from the second WHILE loop, the control goes to the first WHILE and repeats the first step.</p> <p> <strong>Example</strong> </p> <p>The following example will print the multiplication table of 5 up to 10 using the nested WHILE loop.</p> <pre> DECLARE @val1 INT DECLARE @val2 INT SET @val1 = 5 SET @val2 = 1 WHILE @val1 <= 5 44 begin while @val2 <="10" print convert(varchar, @val1) + \' * @val2) techcodeview.com img sql-server-tutorials sql-server-while-loop-8.webp\' alt="SQL Server WHILE LOOP"> <h2>Conclusion</h2> <p>The WHILE loop is a useful method when there is a need to execute a SQL script repeatedly. The article explained how to work with the WHILE loop in MS SQL Server to execute operations such as record insertion and pagination with a simple example. Here we have also learned the BREAK and CONTINUE statements to control the WHILE loop iteration.</p> <hr></=></pre></=></pre></10></pre></=></pre></=></pre></=>
След това ще използваме цикъла WHILE, за да вмъкнем десет записа в тази таблица, като изпълним следния скрипт:
генератор на случайни стойности в java
DECLARE @count INT; SET @count = 1; WHILE @count <= 10 begin insert into bikeshop values(\'bike-\' + cast(@count as varchar), @count*5000) set @count="@count" 1; end; < pre> <p>In this code, we have declared a variable @ <strong>count</strong> and then initialize its value with 1 using a SET clause. Next, we have to define the loop body that executes the INSERT statement to add one record in each execution. The <strong>bike_name column</strong> will append the value of a @count variable with the string <strong>Bike</strong> , and the <strong>price</strong> column determines by the value of a @count variable multiplied by <strong>5000</strong> . The loop will execute until the value of the @count variable becomes FALSE. It means the WHILE loop will execute ten times and <strong>inserts ten records</strong> into the table bikeshop.</p> <p>Now, we can verify all the records of the bikeshop table with the SELECT statement. It will display the following output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-4.webp" alt="SQL Server WHILE LOOP"> <h3>BREAK Statement</h3> <p>SQL Server also allows us to use the BREAK statement in the WHILE loop like programming languages. This statement is used to <strong>immediately stop the current iteration of the loop</strong> , and control flow resumes with the next statement after the loop. In general, we will use the <a href="/sql-server-if-else"> <strong>IF...ELSE statement</strong> </a> to check whether or not a condition has occurred.</p> <p>The following example will explain how to use the BREAK statement in the WHILE loop:</p> <pre> DECLARE @count INT; SET @count = 1; WHILE @count = 6 BEGIN BREAK END SET @Count = @Count + 1 END; </pre> <p>Executing the code will display the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-5.webp" alt="SQL Server WHILE LOOP"> <p>The value of the variable is first evaluated in this code. If it is TRUE, the control enters into the loop and prints the statement. When the variable value is greater than or equal to 6, control enters the IF...ELSE block and executes the BREAK statement to terminate the loop. If an IF...ELSE block fails to meet the condition; then, the loop will keep running until the condition is changed to FALSE.</p> <h3>CONTINUE Statement</h3> <p>SQL Server also allows us to use the CONTINUE statement in the WHILE loop like programming languages. This statement immediately <strong>terminates the current execution of the loop when the specified condition is met</strong> , and control flow returns to the beginning of the loop. In general, the IF...ELSE statement will be used to test whether or not a condition has been met.</p> <p>The CONTINUE statement in the WHILE loop is demonstrated in the following example. In this example, we'll assume that we wish to use a WHILE loop to <strong>print only odd values</strong> . The CONTINUE statement can be used to do this. This example will first <strong>test</strong> whether the variable value is <strong>odd or even</strong> . If it is even, the execution goes inside the IF…ELSE statement blocks and decrement the variable value by one. Then, it will execute the CONTINUE statement and starts a new iteration from the beginning.</p> <pre> DECLARE @Count INT SET @Count = 1 WHILE (@Count <= 1 2="0" 44 20) begin if @count % set + continue end print \'the odd value is=" + CONVERT(VARCHAR, @Count) SET @Count = @Count + 1 END </pre> <p>Executing the code snippet will display the below output:</p> <img src=" techcodeview.com img sql-server-tutorials sql-server-while-loop-6.webp\' alt="SQL Server WHILE LOOP"> <h3>How to implementing paging with WHILE loop in SQL Server?</h3> <p>We can also use the WHILE loop for implementing the paging. Paging allows displaying the subset of records from a table at any particular time. The following example will explain this concept. The WHILE loop in the code will select two records from the bikeshop table at a time. The records that have been chosen are then displayed in the output.</p> <pre> DECLARE @count INT DECLARE @limit INT; SET @count = 0 SET @limit = 2; WHILE @count <10 begin select * from bikeshop order by id offset @count rows fetch next @limit only set + 2; end; < pre> <p>Executing the code snippet will return the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-7.webp" alt="SQL Server WHILE LOOP"> <h3>Nested WHILE Loop</h3> <p>The Nested WHILE Loop in SQL Server is simply a WHILE Loop written inside another WHILE Loop. When we work on multi-layered data, the Nested WHILE loops are essential. Because this concept is useful in extracting the layered data when we want to select them, it is recommended to be careful while using the nested loop.</p> <p> <strong>Syntax</strong> </p> <p>The following syntax illustrate the working of the nested WHILE Loop in SQL Server:</p> <pre> WHILE Expression BEGIN WHILE @Val2 <= 10 begin --second while loop statements sql end --this statement is outside the second --which first -- this < pre> <p>Let us explain this syntax step by step:</p> <p> <strong>Step 1:</strong> The loop starts by checking the first WHILE loop condition, and if it finds a false result, it will exit from While Loop. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution. This block will start the execution of the second WHILE loop. See step 2.</p> <p> <strong>Step 2:</strong> This step will check the condition in the Nested WHILE Loop, and if it is false, the second loop will be exit and execute the statement outside this. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution.</p> <p> <strong>Step 3:</strong> Once all the statements execute from the second WHILE loop, the control goes to the first WHILE and repeats the first step.</p> <p> <strong>Example</strong> </p> <p>The following example will print the multiplication table of 5 up to 10 using the nested WHILE loop.</p> <pre> DECLARE @val1 INT DECLARE @val2 INT SET @val1 = 5 SET @val2 = 1 WHILE @val1 <= 5 44 begin while @val2 <="10" print convert(varchar, @val1) + \' * @val2) techcodeview.com img sql-server-tutorials sql-server-while-loop-8.webp\' alt="SQL Server WHILE LOOP"> <h2>Conclusion</h2> <p>The WHILE loop is a useful method when there is a need to execute a SQL script repeatedly. The article explained how to work with the WHILE loop in MS SQL Server to execute operations such as record insertion and pagination with a simple example. Here we have also learned the BREAK and CONTINUE statements to control the WHILE loop iteration.</p> <hr></=></pre></=></pre></10></pre></=></pre></=>
Изпълнението на кода ще покаже изхода по-долу:
Стойността на променливата първо се оценява в този код. Ако е TRUE, контролата влиза в цикъла и отпечатва оператора. Когато стойността на променливата е по-голяма или равна на 6, управлението влиза в блока IF...ELSE и изпълнява израза BREAK, за да прекрати цикъла. Ако блок IF...ELSE не отговаря на условието; след това цикълът ще продължи да работи, докато условието се промени на FALSE.
ПРОДЪЛЖИ Изявление
SQL Server също ни позволява да използваме командата CONTINUE в цикъла WHILE като езици за програмиране. Това изявление веднага прекратява текущото изпълнение на цикъла, когато определеното условие е изпълнено и контролният поток се връща в началото на цикъла. По принцип операторът IF...ELSE ще се използва за проверка дали дадено условие е изпълнено или не.
Операторът CONTINUE в цикъла WHILE е демонстриран в следния пример. В този пример ще приемем, че искаме да използваме WHILE цикъл за отпечатвайте само нечетни стойности . За това може да се използва операторът CONTINUE. Този пример ще първо тест дали стойността на променливата е четно или нечетно число . Ако е четен, изпълнението преминава вътре в блоковете на инструкции IF…ELSE и намалява стойността на променливата с единица. След това ще изпълни командата CONTINUE и ще започне нова итерация от началото.
щати в САЩ
DECLARE @Count INT SET @Count = 1 WHILE (@Count <= 1 2="0" 44 20) begin if @count % set + continue end print \'the odd value is=" + CONVERT(VARCHAR, @Count) SET @Count = @Count + 1 END </pre> <p>Executing the code snippet will display the below output:</p> <img src=" techcodeview.com img sql-server-tutorials sql-server-while-loop-6.webp\' alt="SQL Server WHILE LOOP"> <h3>How to implementing paging with WHILE loop in SQL Server?</h3> <p>We can also use the WHILE loop for implementing the paging. Paging allows displaying the subset of records from a table at any particular time. The following example will explain this concept. The WHILE loop in the code will select two records from the bikeshop table at a time. The records that have been chosen are then displayed in the output.</p> <pre> DECLARE @count INT DECLARE @limit INT; SET @count = 0 SET @limit = 2; WHILE @count <10 begin select * from bikeshop order by id offset @count rows fetch next @limit only set + 2; end; < pre> <p>Executing the code snippet will return the below output:</p> <img src="//techcodeview.com/img/sql-server-tutorials/44/sql-server-while-loop-7.webp" alt="SQL Server WHILE LOOP"> <h3>Nested WHILE Loop</h3> <p>The Nested WHILE Loop in SQL Server is simply a WHILE Loop written inside another WHILE Loop. When we work on multi-layered data, the Nested WHILE loops are essential. Because this concept is useful in extracting the layered data when we want to select them, it is recommended to be careful while using the nested loop.</p> <p> <strong>Syntax</strong> </p> <p>The following syntax illustrate the working of the nested WHILE Loop in SQL Server:</p> <pre> WHILE Expression BEGIN WHILE @Val2 <= 10 begin --second while loop statements sql end --this statement is outside the second --which first -- this < pre> <p>Let us explain this syntax step by step:</p> <p> <strong>Step 1:</strong> The loop starts by checking the first WHILE loop condition, and if it finds a false result, it will exit from While Loop. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution. This block will start the execution of the second WHILE loop. See step 2.</p> <p> <strong>Step 2:</strong> This step will check the condition in the Nested WHILE Loop, and if it is false, the second loop will be exit and execute the statement outside this. Otherwise, if the result is true, the control goes inside the BEGIN and END block for further execution.</p> <p> <strong>Step 3:</strong> Once all the statements execute from the second WHILE loop, the control goes to the first WHILE and repeats the first step.</p> <p> <strong>Example</strong> </p> <p>The following example will print the multiplication table of 5 up to 10 using the nested WHILE loop.</p> <pre> DECLARE @val1 INT DECLARE @val2 INT SET @val1 = 5 SET @val2 = 1 WHILE @val1 <= 5 44 begin while @val2 <="10" print convert(varchar, @val1) + \' * @val2) techcodeview.com img sql-server-tutorials sql-server-while-loop-8.webp\' alt="SQL Server WHILE LOOP"> <h2>Conclusion</h2> <p>The WHILE loop is a useful method when there is a need to execute a SQL script repeatedly. The article explained how to work with the WHILE loop in MS SQL Server to execute operations such as record insertion and pagination with a simple example. Here we have also learned the BREAK and CONTINUE statements to control the WHILE loop iteration.</p> <hr></=></pre></=></pre></10></pre></=>