How to check if MySQL returns null empty

Question

In DB I have a table with a field called fk ownerID  By default  when I add a new table row  the fk ownerID is empty  In Toad for MySQL  this is shown as  null   If fk ownerID is given a value  and I later remove this value  I set fk ownerID        Now  I have the following code    result    dal- gt getRowByValue  tableName   id     POST  myID         Check to see if any rows where returned if  mysql num rows  result   gt  0      while   row   mysql fetch array  result            ownerID    row  fk ownerID                Now the variable  ownerID should have a number  or not  But I m unsure how to check this  Currently I m doing this   if    strlen  ownerID     0       ownerID     0        ownerID     null       But I m pretty sure only one of these tests should be necessary   What is the best way to check if a row field is empty or null

User · Answer

Also  don t forget the     operator when you re working with numbers that could mean null or 0 or return some form of false or null that isn t what you re looking for

User · Answer

Use empty   and or is null    http   www php net empty http   www php net is null  Empty alone will achieve your current usage  is null would just make more control possible if you wanted to distinguish between a field that is null and a field that is empty

User · Answer

You can use is null   function  http   php net manual en function is-null php   in the comments    mdufour at gmail dot com 20-Aug-2008 04 31 Testing for a NULL field column returned by a mySQL query  Say you want to check if field column    foo    from a given row of the table    bar    when  gt  returned by a mySQL query is null  You just use the    is null      function    connect      qResult mysql query  quot Select foo from bar  quot    while   qValues mysql fetch assoc  qResult        if  is null  qValues  quot foo quot              echo  quot No foo data  quot        else          echo  quot Foo data  quot   qValues  quot foo quot

User · Answer

Suppose    row mysql fetch row  rc  and if you want to check if row 8  is null then do  field  row 8      if  field  echo     else  echo

User · Answer

if    strlen  ownerID     0       ownerID     0       empty  ownerID        if  ownerID is NULL it will be triggered by the empty   test  https   www php net empty

User · Answer

select FOUND ROWS      will return no  of records selected by select query

[php] How to check if MySQL returns null/empty?

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