Best way to check if MySQL results returned in PHP

Question

I m looking for the best way to check and see if any results were returned in a query  I feel like I write this part of code a lot and sometimes I get errors  and sometimes I don t   For example  I run this query to check if a username exists before inserting a new one into the database    result   mysql query  SELECT   FROM          Then I want to check and see if any results were returned  Here is one way I do it   if    result    PERFORM ACTION     If the first way doesn t work  then sometimes this will   if  mysql num rows  result   0    PERFORM ACTION     Then I even saw that I could do it this way the other day   list  total    mysql fetch row  result   if   total  0    PERFORM ACTION     What is the best way to do this

User · Answer

Of all the options above I would use   if  mysql num rows  result   0    PERFORM ACTION     checking against the result like below  if    result    PERFORM ACTION     This will be true if a mysql error occurs so effectively if an error occurred you could then enter a duplicate user-name

User · Answer

Use the one with mysql fetch row because  For SELECT  SHOW  DESCRIBE  EXPLAIN and other statements returning resultset  mysql query   returns a resource on success  or FALSE on error   For other type of SQL statements  INSERT  UPDATE  DELETE  DROP  etc  mysql query   returns TRUE on success or FALSE on error

User · Answer

if  mysql num rows  result   0    PERFORM ACTION     For PHP 5 and 7 and above use mysqli   if  mysqli num rows  result   0    PERFORM ACTION     This gets my vote   OP assuming query is not returning any error  so this should be one of the way

User · Answer

mysqli fetch array   returns NULL if there is no row   In procedural style     if      row   mysqli fetch array   result               no result       else           get the first result in  row         In Object oriented style   if      row    result- gt fetch array                 else           get the first result in  row

User · Answer

result    mysqli- gt query  query   if  result       perform action     this is how i do it  you could also throw an else there with a die

User · Answer

If you would still like to perform the action if the  result is invalid    if  mysql num rows  result          Do stuff   This will account for a 0 and the false that is returned by mysql num rows   on failure

User · Answer

Whenever we do queries to get some data  it is returned as an object  Then most of us convert it to array for looping through the rows easily  In php  empty    function is used to check if an array is empty i e  if it has no data in it  So we can check if returned array representation of query isn t empty by doing like this  if  empty  result                 DO STUFF

User · Answer

One way to do it is to check what mysql num rows returns  A minimal complete example would be the following    if   result   mysql query  sql   amp  amp  mysql num rows  result   gt  0           there are results in  result   else          no results     But it s recommended that you check the return value of mysql query and handle it properly in the case it s false  which would be caused by an error   probably by also calling mysql error and logging the error somewhere

User · Answer

What is more logical then testing the TYPE of the result variable before processing  It is either of type  boolean  or  resource   When you use a boolean for parameter with mysqli num rows  a warning will be generated because the function expects a resource     result   mysqli query  dbs   sql    if gettype  result    boolean       test for boolean     if  result       returned TRUE  e g  in case of a DELETE sql           echo  SQL succeeded          else      returned FALSE         echo  Error      mysqli error  dbs            else      must be a resource     if mysqli num rows  result               process the data                mysqli free result  result

User · Answer

connect   new mysqli  localhost    user    password    db     result    connect- gt query  select   from         count  result- gt num rows  if empty  count    echo Query returned nothing     else  echo query returned results

User · Answer

Usually I use the      triple equals  and   LINE       CLASS   to locate the error in my code    query mysql query  SELECT champ FROM table   or die  SQL Error line      LINE      class     CLASS         mysql error      mysql close     if mysql num rows  query    0        PERFORM ACTION    else       while  r mysql fetch row  query                   PERFORM ACTION

[php] Best way to check if MySQL results returned in PHP?

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