php and regex: search for word in string

Question

How can i found word in string using regex or not in this string

String is Mysql Query

SELECT 
  id,
  name,
  desc,
  (SELECT id as lid FROM comments WHERE lid = id order by id desc limit 1) as lid_com
 FROM posts limit 3

here i want to search for limit in the last of string

string may be

  limit 3
  limit 3, 3
  limit 3 , 3
  limit 3 ,3

3 here may be any number

i tried this regex but i'm beginner

"/ limit [0-9]{0,9}+\,[0-9]{0,9} /i$"

how can i do this

Thank you

may be query is not vaild mysql query but i added it with subquery wth limit word , heres query contain 2 words of limit ^-^ — Mona Abdelmajeed
– Mona Abdelmajeed, Commented Apr 9, 2012 at 12:45
Would this question : "How to find the first word of a string" fit better to what you are looking for ? — FailedDev
– FailedDev, Commented Apr 9, 2012 at 12:46
@FailedDev yes i want to find it in the main query not in the subquery — Mona Abdelmajeed
– Mona Abdelmajeed, Commented Apr 9, 2012 at 12:48

user1237595 · Accepted Answer · 2012-04-09 12:53:11Z

1

$string = 'SELECT
  id,
  name,
  desc,
  (SELECT id as lid FROM comments WHERE lid = id order by id desc limit 1) as lid_com
 FROM posts limit 3 ,3';

echo preg_match('/(limit)\s\d(((\,\s)|(\s\,\s)|(\s\,))\d)?$/i', $string, $matches);  //1
print_r($matches); //$matches['0'] == 'limit 3 ,3'

answered Apr 9, 2012 at 12:53

user1237595

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4 Comments

Mona Abdelmajeed Over a year ago

Thank you @lng , your regex work fine , but not with this limit 3,3

Mona Abdelmajeed Over a year ago

Now its work fine after regex become /(limit)\s\d(((\,\s)|(\s\,\s)|(\s\,))\d)?$/i , but as @kirilloid said limit is not always last statment dev.mysql.com/doc/refman/5.0/en/select.html , this will need some more work :)

user1237595 Over a year ago

Just take out the $ so the regex will match anywhere in the string, not just the end :)

Mona Abdelmajeed Over a year ago

This Will affect sub query if found , i want the main query

globin · Accepted Answer · 2012-04-09 12:51:34Z

1

"/limit[\s]+[\d]+[\s]*,[\s]*[\d]+$/i"

This searches case insesitive for:

"limit"
one or more whitespaces
one or more digits
zero or more whitespaces
a comma
zero or more whitespaces
one or more digits
at the end of the string

answered Apr 9, 2012 at 12:51

globin

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2 Comments

Tom Imrei Over a year ago

maybe add ' posts ' before 'limit' to only get the second occurrence

Mona Abdelmajeed Over a year ago

not work ( without comment on your answer ) , and i will not control the query :(

kirilloid · Accepted Answer · 2012-04-09 12:56:44Z

1

Do not remember, whether LIMIT is always a last SQL statement, so I'd use

/limit\s+(\d+)(?:\s*,\s*(\d+))?(?=[^\n]+\Z)/mi

answered Apr 9, 2012 at 12:56

kirilloid

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3 Comments

Mona Abdelmajeed Over a year ago

Thank you for answer . but this regex work with the subquery too ?? i want to check it in the main query only not sub queries

kirilloid Over a year ago

It matches only those limit statement, which is located on the last line. Parsing arbitrary SQL code with regexes isn't good idea.

kirilloid Over a year ago

Find some SQL code parser and integrate it =) But actually your underlying problem may be solved w/o replacing at all, just try to solve it from another side.

Devart · Accepted Answer · 2012-04-09 13:16:21Z

0

Try this condition -

SELECT * FROM table WHERE column
  REGEXP '(^limit[[:space:]]+[[:digit:]]+[[:space:]]*,[[:space:]]*[[:digit:]]+$)|(^limit[[:space:]]+[[:digit:]]+[[:space:]]*$)';

The first part find strings like 'limit 3,3' -

^limit[[:space:]]+[[:digit:]]+[[:space:]]*,[[:space:]]*[[:digit:]]+$

The second one finds strings like 'limit 3' -

^limit[[:space:]]+[[:digit:]]+[[:space:]]*$

edited Apr 9, 2012 at 13:16

answered Apr 9, 2012 at 13:03

Devart

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