I have a table in SQLite database with data type text, but when I do comparison its not working if I do it this way :
select * from scanned_dbs where db = 'cdd_db';
But if i change the query to:
select * from scanned_dbs where db like 'cdd_db';
It works. But as valex pointed out it will also match cddAdb, cddBdb, ...and so on, so this is not the right way.
One more method I found which is working is this:
select * from scanned_dbs where cast(db as varchar) = 'cdd_db';
So can any one tell me why this is working and not the first one which is direct comparison...
Because an underscore ("_") in the LIKE pattern matches any single character in the string.
So when you use db = 'cdd_db' the only db value that matches is exact 'cdd_db'. But when you use the LIKE operator db like 'cdd_db' then "_" symbol is a pattern so db values that match: cddAdb,cddBdb,cddcdb,cddddb,cdd1db, ....
Related
I've written the following SQL query to return all sites having "id" equal to 2.
SELECT * FROM `sites` WHERE id = '2'
And it works well. The problem is that even if I add some characters after "2" like this :
SELECT * FROM `sites` WHERE id = '2etyupp-7852-trG78'
It returns the same results as above.
How to avoid this ? that's to say return none on the second query ?
Thanks
The reason is that you are mixing types:
where id = '2'
------^ number
-----------^ string
What is a SQL engine supposed to do? Well, the standard approach is to convert the string to a number. So this is run as:
where id = 2
What happens when the string is not a number? In most databases, you get a type conversion error. However, MySQL does implicit conversion, converting the leading digits to a number. Hence, your second string just comes 2.
From this, I hope you learn not to mix data types. Compare numbers to numbers. Compare strings to strings.
Suppose I have a table named 'Customer' with many columns and I want to display all customers who's name ends with 'Thomas'(Lastname = 'Thomas'). The following query shows an empty result(no rows). Also it didn't show any error.
SELECT * FROM Customer WHERE Lastname = 'Thomas';
While executing the following query give me correct result.
SELECT * FROM Customer WHERE Lastname LIKE '%Thomas%';
I would like to know what is the problem with my first query. I am using sqlite3 with Npm. Below is the result of '.show' command(Just in case of the problem is with config).
sqlite> .show
echo: off
explain: off
headers: on
mode: column
nullvalue: ""
output: stdout
separator: "|"
stats: off
width:
Use Like instead of =
Trim to ensure that there arent spaces messing around
so the query will be
SELECT * FROM Customer WHERE trim(Lastname) LIKE 'Thomas';
depending on your types, probably you dont need point 2, since as can be read in mysql manual
All MySQL collations are of type PADSPACE. This means that all CHAR
and VARCHAR values in MySQL are compared without regard to any
trailing spaces
But the point 1 could be the solution. Actually if you want to avoid problems, you should compare strings with LIKE, instead of =.
If You still have problems, probably you will have to use collates.
SELECT *
FROM t1
WHERE k LIKE _latin1 'Müller' COLLATE latin1_german2_ci; #using your real table collation
more information here But specifically with 'Thomas' you shouldn't need it, since it hasn't got any special characters.
Here is the scenario:
I have a SQL select statement that returns a binary data object as a string. This cannot be changed it is outside the area of what I can modify.
So for example it would return '1628258DB0DD2F4D9D6BC0BF91D78652'.
If I manually add a 0x in front of this string in a query I will retrieve the results I'm looking for so for example:
SELECT a, b FROM mytable WHERE uuid = 0x1628258DB0DD2F4D9D6BC0BF91D78652
My result set is correct.
However I need to find a Microsoft SQL Server 2008 compatible means to do this programatically. Simply concatenating 0x to the string variable does not work. Obvious, but I did try it.
Help please :)
Thank you
Mark
My understanding of your question is that you have a column uuid, which is binary.
You are trying to select rows with a particular value in uuid, but you are trying to use a string like so:
SELECT a, b FROM mytable WHERE uuid = '0x1628258DB0DD2F4D9D6BC0BF91D78652'
which does not work. If this is correct, you can use the CONVERT function with a style of 2 to have SQL Server treat the string as hex and not require a '0x' as the first characters:
SELECT a, b
FROM mytable
WHERE uuid = CONVERT(binary(16), '1628258DB0DD2F4D9D6BC0BF91D78652', 2)
I have this query (that runs on Oracle 10g database):
SELECT ge.*, ge.concept AS glossarypivot
FROM s_glossary_entries ge
WHERE (ge.glossaryid = '161' OR ge.sourceglossaryid = '161')
AND (ge.approved != 0 OR ge.userid = 361)
AND concept like 'م%' ORDER BY ge.concept
The query must display all words that begin with the arabic letter "م"
but unfortunately, it returns empty result ..
However, if I run the same query on the same database which runs on MYSQL, it works well and displays the correct result ..
and also, if I run the same query with an english letter (m), like this:
SELECT ge.*, ge.concept AS glossarypivot
FROM s_glossary_entries ge
WHERE (ge.glossaryid = '161' OR ge.sourceglossaryid = '161')
AND (ge.approved != 0 OR ge.userid = 361)
AND concept like 'm%' ORDER BY ge.concept
it displays result correctly and not empty !!
What should I do in order to get this query working the right way on oracle 10 database?
P.S. the oracle database character set is : "AL32UTF8"
thank you so much in advance
Sure that this works in MySQL? I would do this part:
AND concept = 'م'
like this:
AND concept LIKE 'م%'
or because it's arabic and the first char is the right one's like this:
AND concept LIKE '%م'
But i have no idea if Oracle even have LIKE, i never worked with Oracle.
if I put a UTF8 character : " ظ… " instead of the arabic character "م" it will work on oracle ...
The obvious question is, do you have matching data.
You can use SELECT DUMP(concept), DUMP('م') FROM ... to see the bytes that actually form the value. My database gives me 217/133. I believe there are some characters which can have different bytes in UTF-8 but the same physical appearance, though I couldn't say whether this is one of them.
Also, consult the Globalization guide.
i thjink its a mismatch in your oracle client codepage. it should be defined in the same character set as the database, otherwise there will be some character conversion.
I have stored values in my database that look like 5XXXXXX, where X can be any digit. In other words, I need to match incoming SQL query strings like 5349878.
Does anyone have an idea how to do it?
I have different cases like XXXX7XX for example, so it has to be generic. I don't care about representing the pattern in a different way inside the SQL Server.
I'm working with c# in .NET.
You can write queries like this in SQL Server:
--each [0-9] matches a single digit, this would match 5xx
SELECT * FROM YourTable WHERE SomeField LIKE '5[0-9][0-9]'
stored value in DB is: 5XXXXXX [where x can be any digit]
You don't mention data types - if numeric, you'll likely have to use CAST/CONVERT to change the data type to [n]varchar.
Use:
WHERE CHARINDEX(column, '5') = 1
AND CHARINDEX(column, '.') = 0 --to stop decimals if needed
AND ISNUMERIC(column) = 1
References:
CHARINDEX
ISNUMERIC
i have also different cases like XXXX7XX for example, so it has to be generic.
Use:
WHERE PATINDEX('%7%', column) = 5
AND CHARINDEX(column, '.') = 0 --to stop decimals if needed
AND ISNUMERIC(column) = 1
References:
PATINDEX
Regex Support
SQL Server 2000+ supports regex, but the catch is you have to create the UDF function in CLR before you have the ability. There are numerous articles providing example code if you google them. Once you have that in place, you can use:
5\d{6} for your first example
\d{4}7\d{2} for your second example
For more info on regular expressions, I highly recommend this website.
Try this
select * from mytable
where p1 not like '%[^0-9]%' and substring(p1,1,1)='5'
Of course, you'll need to adjust the substring value, but the rest should work...
In order to match a digit, you can use [0-9].
So you could use 5[0-9][0-9][0-9][0-9][0-9][0-9] and [0-9][0-9][0-9][0-9]7[0-9][0-9][0-9]. I do this a lot for zip codes.
SQL Wildcards are enough for this purpose. Follow this link: http://www.w3schools.com/SQL/sql_wildcards.asp
you need to use a query like this:
select * from mytable where msisdn like '%7%'
or
select * from mytable where msisdn like '56655%'