{"id":151,"date":"2019-09-24T07:54:22","date_gmt":"2019-09-24T07:54:22","guid":{"rendered":"http:\/\/sumitjangid.com\/?p=151"},"modified":"2019-09-24T08:03:46","modified_gmt":"2019-09-24T08:03:46","slug":"while-loop","status":"publish","type":"post","link":"http:\/\/sumitjangid.com\/index.php\/2019\/09\/24\/while-loop\/","title":{"rendered":"while Loop"},"content":{"rendered":"\n

Overview of WHILE<\/code> statement<\/h2>\n\n\n\n

The WHILE<\/code> statement is a control-flow statement that allows you to execute a statement block repeatedly as long as a specified is TRUE<\/code>.<\/p>\n\n\n\n

The following illustrates the syntax of the WHILE<\/code> statement:<\/p>\n\n\n\n
12<\/td>WHILE Boolean_expression        { sql_statement | statement_block}  <\/td><\/tr><\/tbody><\/table>\n\n\n\n

In this syntax:<\/p>\n\n\n\n

First, the Boolean_expression<\/code> is an expression that evaluates to TRUE<\/code> or FALSE<\/code>.<\/p>\n\n\n\n

Second, sql_statement | statement_block<\/code> is any Transact-SQL statement or a set of Transact-SQL statements. A statement block is defined using the BEGIN...END<\/code> statement.<\/p>\n\n\n\n

If the Boolean_expression<\/code> evaluates to FALSE<\/code> when entering the loop, no statement inside the WHILE<\/code> loop will be executed.<\/p>\n\n\n\n

Inside the WHILE<\/code> loop, you must change some values to make the Boolean_expression<\/code> returns FALSE<\/code> at some points. Otherwise, you will have an indefinite loop.<\/p>\n\n\n\n

Note that if the Boolean_expression<\/code> contains a SELECT<\/a><\/code> statement, it must be enclosed in parentheses.<\/p>\n\n\n\n

To exit the current iteration of the loop immediately, you use the BREAK<\/code> statement. To skip the current iteration of the loop and start the new one, you use the CONTINUE<\/code> statement.<\/p>\n\n\n\n

SQL Server WHILE<\/code> example<\/h2>\n\n\n\n

Let\u2019s take an example of using the SQL Server WHILE<\/code> statement to understand it better.<\/p>\n\n\n\n

The following example illustrates how to use the WHILE<\/code> statement to print out numbers from 1 to 5:<\/p>\n\n\n\n
1234567<\/td>DECLARE @counter INT = 1; WHILE @counter <= 5BEGIN    PRINT @counter;    SET @counter = @counter + 1;END<\/td><\/tr><\/tbody><\/table>\n\n\n\n

In this example:<\/p>\n\n\n\n

First, we declared the @counter<\/code> variable<\/a> and set its value to one.<\/p>\n\n\n\n

Then, in the condition of the WHILE<\/code> statement, we checked if the @counter<\/code>is less than or equal to five. If it was not, we printed out the @counter<\/code> and increased its value by one. After five iterations, the @counter<\/code> is 6 which caused the condition of the WHILE<\/code> clause evaluates to FALSE<\/code>, the loop stopped.<\/p>\n\n\n\n

The following shows the output:<\/p>\n\n\n\n
12345<\/td>12345<\/td><\/tr><\/tbody><\/table>\n","protected":false},"excerpt":{"rendered":"

Overview of WHILE statement The WHILE statement is a control-flow statement that allows you to execute a statement block repeatedly as long as a specified is TRUE. The following illustrates the syntax of the WHILE statement: 12 WHILE Boolean_expression        { sql_statement… <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2,18,19],"tags":[],"_links":{"self":[{"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/posts\/151"}],"collection":[{"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/comments?post=151"}],"version-history":[{"count":1,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/posts\/151\/revisions"}],"predecessor-version":[{"id":152,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/posts\/151\/revisions\/152"}],"wp:attachment":[{"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/media?parent=151"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/categories?post=151"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/sumitjangid.com\/index.php\/wp-json\/wp\/v2\/tags?post=151"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}