php noob in training

[esostigma]

hi all,
first off thanks to any help i receive.

ok, i am being given an open book test in a way to asses my current knowledge (zero) of php. i am just scrutinizing and breaking it down so that i can understand what the .... is going on.

i will have many questions no doubt.

here is what i'm looking at right now:

Code:
select distinct '** ERROR ** NULL Character in : primary_mst.box_addr_stop=' || box_addr_stop Alert from primary_mst where
substr(box_addr_stop,1,1) is NULL or
substr(box_addr_stop,2,1) is NULL or
substr(box_addr_stop,3,1) is NULL or
substr(box_addr_stop,4,1) is NULL or
substr(box_addr_stop,5,1) is NULL or
substr(box_addr_stop,6,1) is NULL or
substr(box_addr_stop,7,1) is NULL or
substr(box_addr_stop,8,1) is NULL;


here is what i'm to do:
Code:
Include information about the type of query, the data (if any) the query returns, what (if anything) the query is looking for, and any messages the query produces under various circumstances.

first question: am i just supposed to pop this into phpmyadmin and write down error msgs, results, etc...? i really need to know what is being done by this code here. i can identify substr may mean substring... and that the person is trying to possibly look for errors in a variable or table called: primary_mst.box_addr_stop am i right in guess that? please if anyone could just explain it to me what is going on here. thank you , it is much appreciated any help.

first thoughts:
.. looking for errors in a table called: box_addr_stop
what does =' mean?
what does primary_mst. mean? is it that primary_mst. is the name of the table and the box_addr_stop is a variable containing data in that table?
this is an array? are the numbers locations of cells?

[Donny Bahama]

Originally Posted by esostigma

Code:
select distinct '** ERROR ** NULL Character in : primary_mst.box_addr_stop=' || box_addr_stop Alert from primary_mst where
substr(box_addr_stop,1,1) is NULL or
substr(box_addr_stop,2,1) is NULL or
substr(box_addr_stop,3,1) is NULL or
substr(box_addr_stop,4,1) is NULL or
substr(box_addr_stop,5,1) is NULL or
substr(box_addr_stop,6,1) is NULL or
substr(box_addr_stop,7,1) is NULL or
substr(box_addr_stop,8,1) is NULL;

OK, first off, that's the funkiest looking query I've EVER seen. I can't imagine that it would return anything meaningful. For all those lines beginning with "substr", have a look here: http://us2.php.net/substr

am i just supposed to pop this into phpmyadmin and write down error msgs, results, etc...?

Not sure I understand your question, but if you're to be given access to a database that has the referenced table and field, I'd definitely plug it into phpmyadmin and have a look.

i really need to know what is being done by this code here. i can identify substr may mean substring... and that the person is trying to possibly look for errors in a variable or table called: primary_mst.box_addr_stop am i right in guess that?

Again, that's the strangest looking query I've ever seen and I'd be surprised if that could run, but it depends on the database, I suppose. I can't help you much beyond that.

what does =' mean?

The apostrophe is closing a string. The string begins with "**", so the entire string is:
** ERROR ** NULL Character in : primary_mst.box_addr_stop=
That's why this is sucha bizaree looking query. How do you select a distinct ** ERROR ** NULL Character in : primary_mst.box_addr_stop=

what does primary_mst. mean? is it that primary_mst. is the name of the table and the box_addr_stop is a variable containing data in that table?

primary_mst is the name of a table and box_addr_stop is a field in that table.

this is an array? are the numbers locations of cells?

No. Each of those substr lines represents a character (that's the ",1" in each of them.) Once more, no idea what the heck this should return - or even if it would run.

HTH a little. Maybe someone with industrial strength sql knowledge can shed more light on this. Good luck!

[esostigma]

wow, ok thank you grande. you've been a big help.


here is my next one: can you break this down for me as well?

Code: Select all

  	Student Programmers Test 1 of 2 	 	 	 	 	 	 	 	 	  select distinct '** WARN **  Date will convert to NULL: primary_mst.box_name_change=' || box_name_change Alert from primary_mst where
  (box_name_change < '0001' or box_name_change > '99999999') and
  box_name_change <> ' ' and box_name_change <> '00000000';

[Donny Bahama]

Originally Posted by esostigma

can you break this down for me as well?

Code: Select all

      Student Programmers Test 1 of 2
select distinct '** WARN **  Date will convert to NULL: primary_mst.box_name_change=' || box_name_change Alert from primary_mst where
  (box_name_change < '0001' or box_name_change > '99999999') and
  box_name_change <> ' ' and box_name_change <> '00000000';

I'll do the best I can, but these queries are very foreign to me.
Basically you're looking for some records in a field called "box_name_change" in a table called "primary_mst".

The section that I've highlighted in orange is basically saying, show me records where the box_name_change field is set to a value that is less than 0001 or greater than 99999999 but not equal to 00000000 and not equal to '' (nothing/empty). Most likely this query would return no records unless there are records where box_name_change has a value greater than 99999999.

"distinct" means don't show me duplicate rows. The two vertical lines means "or", but the stuff in blue, purple and red is totally Greek to me.

It's interesting that this is a PHP course, since the focus appears to be on SQL. FYI - there's a great resource for learning the basics of SQL here: http://www.sqlcourse.com - I highly recommend it. You can breeze through it pretty quickly and it will help you to understand better some of what's going on here.

[esostigma]

ok super great response amigo, thank you so much. question: what is this---> ** WARN **

and what is this from the first one at the top of the post:
** ERROR **

[Donny Bahama]

No idea. Sorry.

[esostigma]

that's ok, thank you!