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)
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.
In a column in a SQL Server database table, the value has a format of X=****;Y=****;Z=5****, where the asterisks represent strings of any lengths and of any values. What I need to do is to change that 5 to a 4 and keep the rest of the string unchanged.
Is there a way to use something like regular expressions to achieve what I want to do? If not using regular expressions, can it be done at all?
MS SQL sadly doesn't have any built in regex support (although it can be added via CLR) but if the format is fixed so that the part you want to change isZ=5toZ=4then usingREPLACEshould work:
REPLACE(your_string,'Z=5','Z=4')
For example:
declare #t table (str varchar(max))
insert #t values
('X=****;Y=****;Z=5****'),
('X=****;Y=**df**;Z=3**sdf**'),
('X=11**;Y=**sdfdf**;Z=5**')
update #t
set str = replace(str,'Z=5','Z=4')
-- or a slightly more ANSI compliant and portable way
update #t
set str = SUBSTRING(str,0, CHARINDEX('Z=5', str)) + 'Z=4' + SUBSTRING(str, CHARINDEX('Z=5', str)+3,LEN(str))
select * from #t
str:
X=****;Y=****;Z=4****
X=****;Y=**df**;Z=3**sdf**
X=11**;Y=**sdfdf**;Z=4**
We need more information. Under what circumstances should 5 be replaced by 4? If it's just where it occurs as the first character after the Z=, then you could simply do...
set Col = Replace(Col,'Z=5','Z=4')
Or, do you just want to replace 5 with 4 anywhere in the column value. In which case you'd obviously just do...
set Col = Replace(Col,'5','4')
Or possibly you mean that 5's should be replaced by 4's anywhere within the value after Z= which would be a lot harder.
update Table set Field = replace(Field, ';Z=5', ';Z=4')
And let's hope that your asterisked data doesn't contain semicolons and equality signs...
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, ....
I am trying to connect a Filemaker DB to Firebird SQL DB in both ways import to FM and export back to Firebird DB.
So far it works using the MBS Plug-in but FM 13 Pro canot handle NULL.
That means that for example Timestamp fields that are empty (NULL) produce a "0" value.
Thats means in Time something like 01.01.1889 00:00:00.
So my idea was to simply ignore fields containing NULL.
But here my poor knowlege stops.
First I thought I can do this with WHERE, but this is ignoring whole records sets:
SELECT * FROM TABLE WHERE FIELD IS NOT NULL
Also I tried to filter it later on like this:
If (IsEmpty (MBS("SQL.GetFieldAsDateTime"; $command; "FIELD") ) = 0 ; MBS("SQL.GetFieldAsDateTime"; $command; "FIELD"))
With no result either.
This is a direct answer to halfbit's suggestion, which is correct but not for this SQL dialect. In a query to provide a replacement value when a field is NULL you need to use COALESCE(x,y). Where if X is null, Y will be used, and if Y is null then the field is NULL. Thats why it is common for me to use it like COALESCE(table.field,'') such that a constant is always outputted if table.field happens to be NULL.
select COALESCE(null,'Hello') as stackoverflow from rdb$database
You can use COALESCE() for more than two arguments, I just used two for conciseness.
I dont know the special SQL dialect, but
SELECT field1, field2, value(field, 0), ...FROM TABLE
should help you:
value gives the first argument, ie, your field if it is NOT NULL or the second argument if it is.
I'm trying to query an xml column using an IN expression. I have not found a native XQuery way of doing such a query so I have tried two work-arounds:
Implement the IN query as a concatenation of ORs like this:
WHERE Data.exist('/Document/ParentKTMNode[text() = sql:variable("#Param1368320145") or
text() = sql:variable("#Param2043685301") or ...
Implement the IN query with the String fn:contains(...) method like this:
WHERE Data.exist('/Document/Field2[fn:contains(sql:variable("#Param1412022317"), .)]') = 1
Where the given parameter is a (long) string with the values separated by "|"
The problem is that Version 1. doesn't work for more than about 50 arguments. The server throws an out of memory exception. Version 2. works, but is very, very slow.
Has anyone a 3. idea? To phrase the problem more complete: Given a list of values, of any sql native type, select all rows whose xml column has one of the given values at a specific field in the xml.
Try to insert all your parameters in a table and query using sql:column clause:
SELECT Mytable.Column FROM MyTable
CROSS JOIN (SELECT '#Param1' T UNION ALL SELECT '#Param2') B
WHERE Data.exist('/Document/ParentKTMNode[text() = sql:column("T")