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Checking for matching record in MySQL table |
We can just check MySql table to verify whether a record exist or not. Here we are not interested in collecting the actual data from table. We are interested in getting a reply of TRUE or FALSE from our command. We will try for one line command using PHP.
We need such a query while working on a member signup script. Here when member enters a userid in the signup form we need to verify with our existing table to know if the userid is already used by some other member. Some time we will have different pages with access to different groups of members ( here the members have different level of access ). So when the member visit a page we will check with our table the member has required level of privilege or not.
This conditional checking is done by using if condition in PHP. Let us see the code for checking the userid exist inside a MySQL table or not.
if(mysql_num_rows(mysql_query("SELECT userid FROM plus_signup WHERE userid = '$userid'"))){
// Code inside if block if userid is already there
}
The above sql query will return TRUE or FALSE depending on the presence of userid in MySQL table.
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