while row mysql fetch array result - how many loops are being performed

Question

if      query    SELECT col1 col2 col3 FROM table WHERE id  gt  100   result   mysql query  query     for this action   while   row   mysql fetch array  result                is this doing 1 loop  iterated x times    and for this one    row   mysql fetch array  result  foreach  row as  r              is this doing 2 loops  iterated x times    where x is the number of results    EDIT   ok thanks guys  ok I basically phrased this question really  really badly   in retrospect it should have been        does mysql fetch array   only return one   row each time it is called    I an now happy that my understanding of mysql fetch array   was v  incorrect   thanks for your time

User · Answer

query    SELECT col1 col2 col3 FROM table WHERE id  gt  100   result   mysql query  query   if mysql num rows  result  gt 0     while  row   mysql fetch array      here you can use many functions such as mysql fetch assoc   and other      It returns 1 row to your variable that becomes array and automatically go to the next result string   Echo  row  col1       Echo  row  col2       Echo  row  col2

User · Answer

It depends how many rows are returned in  results  and how many columns there are in  row

User · Answer

I m assuming mysql fetch array   perfroms a loop  so I m interested in if using a while   in conjunction with it  if it saves a nested loop    No  mysql fetch array just returns the next row of the result and advances the internal pointer  It doesn t loop   Internally it may or may not use some loop somewhere  but that s irrelevant    while   row   mysql fetch array  result                This does the following    mysql fetch array retrieves and returns the next row the row is assigned to  row the expression is evaluated and if it evaluates to true  the contents of the loop are executed the procedure begins anew     row   mysql fetch array  result   foreach  row as  r                 This does the following    mysql fetch array retrieves and returns the next row the row is assigned to  row foreach loops over the contents of the array and executes the contents of the loop as many times as there are items in the array   In both cases mysql fetch array does exactly the same thing  You have only as many loops as you write  Both constructs do not do the same thing though  The second will only act on one row of the result  while the first will loop over all rows

User · Answer

Considering only one row is returned  only one loop will be done in both cases  Though it will check for the loop entering condition twice on each

User · Answer

For the first one  your program will go through the loop once for every row in the result set returned by the query  You can know in advance how many results there are by using mysql num rows     For the second one  this time you are only using one row of the result set and you are doing something for each of the columns  That s what the foreach language construct does  it goes through the body of the loop for each entry in the array  row  The number of times the program will go through the loop is knowable in advance  it will go through once for every column in the result set  which presumably you know  but if you need to determine it you can use count  row

User · Answer

Yes  mysql fetch array   only returns one result  If you want to retrieve more than one row  you need to put the function call in a while loop   Two examples    This will only return the first row   row   mysql fetch array  result     This will return one row on each loop  until no more rows are available from the result set  while  row   mysql fetch array  result           Do stuff with contents of  row

User · Answer

The first row      result   mysql query  query       return php db resource   The second row    while   row   mysql fetch array  result       Loops all the records returned by the query   Use mysql fetch assoc instead In that case the row has key  value pairs  In the while just put this  print r  row  and you will understand If you use mysql fetch assoc the format of the row will be      row  column1 name     column1 value     row  column2 name     column2 value      For this one    row   mysql fetch assoc  result    foreach   row as  columnName   gt   columnValue                      You will get the firs row from the query and you will iterate all columns in the first result of the query

[php] while ($row = mysql_fetch_array($result)) - how many loops are being performed?

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