How to not return rows

Question

I'm asking this without code because I want to know a lot of ways of how to NOT return rows? What I'm now using is just not so neat. What i'm now using is '1=2' which allways returns in no rows.

So what i'm asking is a nice and neat way on how to NOT return rows in an sql statement.

UPDATE:

$sql = 'SELECT `a`.`id`, 
                   `a`.`action_id`, 
                   DATE_FORMAT(FROM_UNIXTIME(a.`time`), "%d-%m-%Y") as `date`,
                   DATE_FORMAT(FROM_UNIXTIME(a.`time`), "%H:%i") as `time`,
                   `a`.`amount_other_callers`, 
                   `a`.`additional_data_incident`, 
                   `a`.`additional_data_result`, 
                   `a`.`additional_data_messagequality_start`, 
                   `a`.`additional_data_messagequality_end`, 
                   `a`.`additional_data_smsquality_start`, 
                   `g`.`name` AS gemeente
        FROM `actions` a
        INNER JOIN actions_geo_communities AS ac
            ON ac.lnk_action_id = a.id
        INNER JOIN geodata_communities g
            ON ac.lnk_community_id = g.id ';
    if(Auth::user()->unit_id > 0) {
        $sql.= '    INNER JOIN actions_geo_units AS au
                        ON au.lnk_action_id = a.id ';
    }
    if(Session::get('tk') === "1" && Session::get('ntk') === "1")
    {
        $sql.= '    WHERE `a`.`aangevuld` = 0 AND `a`.time > 1388530800'; 
    }
    else if (Session::get('tk') == 1)
    {
        $sql.= '    WHERE `a`.`aangevuld` = 0 AND `a`.`tk` = 1 AND `a`.time > 1388530800';
    }
    else if (Session::get('ntk') == 1)
    {
        $sql.= '    WHERE `a`.`aangevuld` = 0 AND `a`.`tk` = 0 AND `a`.time > 1388530800';
    }
    else
    {
        $sql.= '    WHERE 1=2';
    }
    if(Auth::user()->unit_id > 0) {
        $sql.= ' AND `au`.`lnk_unit_id` = ' . Auth::user()->unit_id . ' ';
    }       
    if(!empty($not_arr)) {
        $sql.= ' AND `a`.`id` NOT IN (' . implode(',', $not_arr) . ') ';
    }

Answer 1

Best answer for this is not run query , you didn't need any data so why you stress your database

In your case check if two or one check box is checked first then run your query otherwise don't run it at all

Answer 2

I've had this case when a module needed to augment the SQL that other modules have assembled. Based on what I knew in advance about the structure of incoming SQL-parts, I did one of these: when I just had a WHERE condition I transformed it to FALSE AND (<original_where) or simply FALSE if it did not break the other modules. In other cases (when complex queries had multiple WHERE clauses and other clauses after WHERE) I had the luck that the system did not use LIMITs, so I was free to append LIMIT 0