PHP | is_null() Function Last Updated : 05 Oct, 2021 Comments Improve Suggest changes Like Article Like Report The is_null() function is an inbuilt function in PHP which is used to find whether a variable is NULL or not. Syntax: boolean is_null ( $var ) Parameters: This function accepts a single parameter as shown in above syntax and described below. $var: Variable to check if it is NULL or not. Return value: It returns a boolean value. That is, it returns TRUE when $var will be NULL, otherwise it returns FALSE. Below programs illustrate the is_null() function in PHP: Program 1: PHP <?php // PHP code to demonstrate the working of is_null() function $var1 = NULL; $var2 = "\0"; // "\0" means "\0" $var3 = "NULL"; $var4 = 0; // $var1 has NULL value, so always give TRUE is_null($var1) ? print_r("True\n") : print_r("False\n"); // $var2 has '\0' value which consider as null in // c and c++ but here taken as string, gives FALSE is_null($var2) ? print_r("True\n") : print_r("False\n"); // $var3 has NULL string value so it will false is_null($var3) ? print_r("True\n") : print_r("False\n"); // $var4 is 0, gives FALSE is_null($var4) ? print_r("True\n") : print_r("False\n"); ?> Output: True False False False Program 2: PHP <?php // PHP code to demonstrate the working of // is_null() function function check_null($var) { return (is_null($var) ? "True" : "False"); } echo check_null(NULL) . "\n"; echo check_null(null) . "\n"; echo check_null(Null) . "\n"; echo check_null(NUll) . "\n"; echo check_null(NULl) . "\n"; echo check_null(nulL) . "\n"; echo check_null(nuLL) . "\n"; echo check_null(nULL) . "\n"; echo check_null(Nul) . "\n"; echo check_null(false) . "\n"; ?> Output: True True True True True True True True False False Reference: http://php.net/manual/en/function.is-null.php Comment More infoAdvertise with us Next Article PHP | is_null() Function M Mithun Kumar Follow Improve Article Tags : Misc Web Technologies PHP PHP-function Practice Tags : Misc Similar Reads SQL Commands | DDL, DQL, DML, DCL and TCL Commands SQL commands are crucial for managing databases effectively. These commands are divided into categories such as Data Definition Language (DDL), Data Manipulation Language (DML), Data Control Language (DCL), Data Query Language (DQL), and Transaction Control Language (TCL). 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