How am I going to use BETWEEN Operator with Text Value or what is the right syntax when you will select all products with a ProductName for example ending with any of the letter BETWEEN 'C' and 'M'?
Most SQL dialects provide the RIGHT() function. This allows you to do:
WHERE RIGHT(TextValue, 1) BETWEEN 'C' AND 'M'
If your database doesn't have this function, you can do something similar with the built-in functions. Also, the exact comparison might depend on the collation of the column/table/database/server. Sometimes comparisons are independent of case and sometimes they are dependent on case.
In case you are interested in an alternative method (which does work with the w3schools SQL editor), you can also use the LIKE operator:
WHERE ProductName LIKE '%[c-m]'
This will get you all Product Names ending on any character between C and M.
(It does work with the w3schools SQL Editor.)
In this case, the LIKE operator is using two wildcard characters:
1.%
Any string of zero or more characters.
2.[c-m]
Any single character within the specified range ([a-f]) or set
([abcdef]).
You can find more information about the LIKE operator here:
https://msdn.microsoft.com/en-us/library/ms179859.aspx
Related
I have a collection of strings and want to filter out those where the last four characters are: (alpha)(alpha)(number)(number).
I know I can make a substring of each of these and separately, but what is the method to determine the types of the characters in the sequence?
This is for SQL in Hive.
You can use regular expressions. Something like:
where col regexp '[a-zA-Z]{2}[0-9]{2}$'
I need to determine if all rows in varchar column in a db contain any characters outside of the particular set below:
abcdefghijklmonpqrstuvwxyzABCDEFGHIJKLMONPQRSTUVWXYZ.-#,1234567890/\&%();:+#_*?|=''
I tried this but am not sure if it is correct:
select AccName
from Transactions
where AccName not like '%[!abcdefghijklmonpqrstuvwxyzABCDEFGHIJKLMONPQRSTUVWXYZ.-#,1234567890/\&%();:+#_*?|='']%'
Should this work?
Any help appeciated.
You cannot use a regular expression inside an ordinary LIKE condition in a query. If you want to use regular expressions, you will have to use a special operator. In MySQL, you could try the following:
SELECT AccName
FROM Transactions
WHERE AccName REGEXP [!abcdefghijklmonpqrstuvwxyzABCDEFGHIJKLMONPQRSTUVWXYZ.-#,1234567890/\&%();:+#_*?|='']%';
If this doesn't run to boot, then you may have to tidy up the regular expression you gave. And as marc_s asked, the exact regular expression and query will depend on the DB system you are using.
Database management systems vary in their support for matching regular expressions. Examples below use PostgreSQL, which supports POSIX regular expressions, along with other flavors. Examples below also test for case-sensitive matches to avoid sentences like "'Mike' doesn't not match the regular expression".
AFAIK, no DBMS lets you mix the like operator with a regular expression.
A like expression in the form column_name like '%a%' will match 'a' if it appears anywhere in the column. But you need your regular expression to match on the whole value of the column. Anchor the regular expression at the start and end of each value (^ and $), and tell the dbms to match one or more instances (+) of the atom.
select 'Mike' ~ '^[a-zA-Z0-9]+$'; -- 'Mike' matches the regex
Write a failing test.
select 'Mike?' ~ '^[a-zA-Z0-9]+$'; -- 'Mike?' doesn't match the regex
Add the question mark to the regex, and verify the test succeeds.
select 'Mike?' ~ '^[a-zA-Z0-9?]+$'; -- 'Mike?' matches the regex
Repeat failing test and succeeding test for each character. When you've caught all the characters you want, invert the logic using the !~ operator in place of the ~ operator.
When your data is clean move this into a CHECK constraint.
PostgreSQL pattern matching
Trying to select from table where the format can be either 1/2/2014, 1-2-2014 or 1_2_2014 in a text field. There's other text involved outside of this format but it shouldn't matter, but that's why this is text not a date type.
I tried '%[-,_,/]%[-,_,/]%' which doesn't work, and I've tried escaping the special characters in the brackets such as %[-,!_,/]%[-,!_,/]%' ESCAPE '!' which also doesn't work. Any suggestions?
I wanted to avoid using three searches like,
LIKE '%/%/%'
OR '%-%-%'
OR '%!_%!_%' ESCAPE '!'
EDIT: Using SQLite3
There is no regex like behavior in using the LIKE operator in SQL. You would have use two expressions and OR them together:
select * from table
where column like '%-%-%'
or column like '%/%/%'
Thanks for the information. I ended up switching to the GLOB operator which support [] in SQLite.
The Example was altered to GLOB '?[/-_]?[/-_]??*' Where * serves as % and ? serves as _ for the GLOB function.
Also thanks to Amadeaus9 for pointing out minimum characters between delimiters so that '//' isn't a valid answer.
If you're using T-SQL (AKA SQL Server) you don't want to have commas in the character set - i.e. LIKE '%[/_-]%[/_-]%'. However, keep in mind that this can match ANYTHING that has, anywhere within it, any two characters from the set.
EDIT: it doesn't looke like SQLite supports that sort of use of its LIKE operator, based on this link.
Relevant quote:
There are two wildcards used in conjunction with the LIKE operator:
The percent sign (%)
The underscore (_)
However, you may want to take a look at this question, which details using regex in SQLite.
It is not possible using the LIKE syntax.
However Sqlite3 would support the REGEXP operator; this is syntactic sugar for calling an user defined function that actually does the matching. If provided by your platform, then you could use for example
x REGEXP '.*[/_-].*[/_-].*'
I have this regular expression in my sql query
DECLARE #RETURN_VALUE VARCHAR(MAX)
IF #value LIKE '%[0-9]%[^A-Z]%[0-9]%'
BEGIN
SET #RETURN_VALUE = NULL
END
I am not sure, but whenever I have this in my row 12 TEST then it gives me the value of 12, but if I have three digit number then it filters out the three digit numbers.How can I modify the regular expression to return me the three digits numbers too.
any help will be appreciated.
SQL doesn't have regular expressions: it has SQL wildcard expressions. They are much simpler than regular expressions and long predate regular expressions. For instance, there is no way to specify alternation (a|b) or repetition ( a*, a+, a?, a{m,n} ) such as you might find in a regular expression.
The 'like expression' that you have
LIKE '%[0-9]%[^A-Z]%[0-9]%'
will match any string containing the following pattern anywhere in the string
zero or more of any character, followed by...
a single decimal digit, followed by...
zero or more of any character, followed by...
a single character other than A–Z (whether it's case sensitive or not depends on the collating sequence in use), followed by...
zero or of any character, followed by...
a single decimal digit, followed by...
zero or more of any character
One should note that the % is likely to match perhaps more than you might like.
Have you tried ([0-9]*). I believe that this will capture every digit for you. However, I am not as strong at regex. When I ran this through rubular, it worked, though :) BTW, rubular is a great way to test out regular expressions
You can easily create a SQL CLR function and use this in your queries. Visual Studio has a project template for this and makes deploying the functions a snap.
Here is more information from Microsoft about how to create the function and how to use it (for boolean matches and for data extraction).
First of all, note that this is not really a "regular expression", it's a SQL-specific form of wildcard matching. You are very limited in what you can accomplish with SQL wildcards. As one example, you cannot "optionally" match a specific character or character set.
Your expression, as you've written it, will match any value that contains two digits with at least one non-letter character in between them, meaning it will match:
111
1^1
1?7
1AAAAAAAAAAA?AAAAAAAAA1
-----------------------5-----------------3-------
And infinitely more items of a similar structure.
Oddly, one string that would not match this pattern is "12 TEST" because there is no character between the 1 and 2. The pattern also won't "give you" the value of 12 back because it's not a parsing expression, just a matching expression: it returns 1 (true) or 0 (false).
There is clearly something else going on in your application, possibly even an actual regular expression, but it has nothing to do with the SQL you've included here.
I need to find out how many rows in a particular field in my sql server table, contain ONLY non-alphanumeric characters.
I'm thinking it's a regular expression that I need along the lines of [^a-zA-Z0-9] but Im not sure of the exact syntax I need to return the rows if there are no valid alphanumeric chars in there.
SQL Server doesn't have regular expressions. It uses the LIKE pattern matching syntax which isn't the same.
As it happens, you are close. Just need leading+trailing wildcards and move the NOT
WHERE whatever NOT LIKE '%[a-z0-9]%'
If you have short strings you should be able to create a few LIKE patterns ('[^a-zA-Z0-9]', '[^a-zA-Z0-9][^a-zA-Z0-9]', ...) to match strings of different length. Otherwise you should use CLR user defined function and a proper regular expression - Regular Expressions Make Pattern Matching And Data Extraction Easier.
This will not work correctly, e.g. abcÑxyz will pass thru this as it has a,b,c... you need to work with Collate or check each byte.