| how to compare two instances using MySQL REGEXP Function
how to compare two instances using MySQL REGEXP Function |
parorrey
msg:1578703 | 5:46 pm on Dec 22, 2005 (gmt 0) |
hi,
can somebody tell me what m i doing wrong in this MySQL statement.
i want to compare '/' at the start and end of the string in my Link field which can have any chracters from 'a-z' and '-' and it cant have '/' again in the middle of string, just at start and end. i ve tried the following statement and other variations of it but to no avail.
SELECT Name, Link FROM Table WHERE Link REGEXP '^/[a-z-]/$'please help.
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coopster
msg:1578704 | 10:51 pm on Dec 22, 2005 (gmt 0) |
Are you trying to find one or more instances of those characters? Use the plus sign. Use the asterisk for zero or more.SELECT Name, Link FROM Table WHERE Link REGEXP '^/[a-z-]+/$';
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parorrey
msg:1578705 | 3:27 am on Dec 23, 2005 (gmt 0) |
exactly & that worked like a charm. :D
on another note, what if we want to exclude '/' from the string,
for instance, i ve records '/category/' or '/detailed-name-category/' which i want to match but i also have such records like '/category/subcategory/' or '/detailed-name-category/detailed-name-subcategoery/' which i dont want to match, and in your provided statement they dont, is this statment
SELECT Name, Link FROM Table WHERE Link REGEXP '^/[a-z-]+/$';
explicitly exclude '/' from the string apart from start and end so that only categories match and not the subcat or any other records.
but this statement does what i want to do in anycase, i m just trying to dig a bit deeper.
thnx
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parorrey
msg:1578706 | 7:45 am on Dec 23, 2005 (gmt 0) |
ok , got it now completely, SELECT Name, Link FROM Table WHERE Link REGEXP '^/[a-z-]+/$'; in the aboive staement, we are explicitly defining which chracters to match [a-z-]+ and it skipped '/' in the middle of string.
thnx.
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coopster
msg:1578707 | 3:12 pm on Dec 23, 2005 (gmt 0) |
Exactly. Since the slash character (/) is not represented in the character class (the *stuff* in between the brackets ([]) ) then it is not a valid matching character. And the caret (^) and dollar sign are anchors, they say that the pattern must begin with the anchor specified as well as end with the anchor specified -- in this case it is the slash character.
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