Can anyone advise where i'm going wrong with the syntax here please?
I have this query which returns 26 rows
SELECT firstname, lastname
FROM author
WHERE authorid IN (
SELECT authorid
FROM written_by
JOIN book ON written_by.bookdescid = book.bookdescid
WHERE UPPER (book.title) LIKE UPPER ('%electric%')
AND NOT UPPER (written_by.role) LIKE UPPER('%translator%'));
This appears to be correct and the reason I am using UPPER and ('%example%') like this is for variations in capitalization.
However, when I try and add into the query to also pick up where the book subtitle also includes 'electric' I am somehow getting the syntax wrong as it returns less rows? If anything it should be the same or more... I've tried a few variations but this one below is what i thought would work..
SELECT firstname, lastname
FROM author
WHERE authorid IN (
SELECT authorid
FROM written_by
JOIN book ON written_by.bookdescid = book.bookdescid
WHERE UPPER (book.title) OR (book.subtitle) LIKE UPPER ('%electric%')
AND NOT UPPER (written_by.role) LIKE UPPER('%translator%'));
You must use separate expressions with the operator LIKE:
WHERE ((UPPER(book.title) LIKE '%ELECTRIC%') OR (UPPER(book.subtitle) LIKE '%ELECTRIC%'))
AND (UPPER(written_by.role) NOT LIKE '%TRANSLATOR%');
Also use UPPER() only for the columns and provide the string literals in uppercase.
Related
String record : Blueoba Mountain Company
SQL Query :
SELECT from table
WHERE CATSEARCH(account_partner_name_type,'%Blueoba% %Mountain% %Company%', NULL) > 0)
where rn <=500;
If I write the full name of the string in the query (i.e.%Blueoba% %Mountain% %Company%) then it gives me the record.
But if I write %Blueoba% %Mountain% %Comp% or %Blue% %Company% or %Comp% then its not returning any record.
So ideally, if I write a word %comp% then it should search all the records which contains 'comp' word and show the records but its not showing.
Can anybody suggest something?
You can try using wild card characters
SELECT * from table
WHERE account_partner_name_type like '%Blueoba%'
and rn <=500;
I need to get all the matches of a regular expression in a text field in a MariaDB table. As far as I know REGEXP_SUBSTR is the way to go to get the value of the match of a regular expression in a text field, but it always returns after the first match and I would like to get all matches.
Is there any way to do this in MariaDB?
An example of the content of the text field would be:
#Generation {
// 1
True =>
`CP?:24658` <= `CPV?:24658=57186`;
//`CP?23432:24658` <= `CPV?:24658=57186`
// 2
`CP?:24658` <> `CPV?:24658=57178` =>
`CP?:24656` <> `CPV?:24656=57169`;
And the select expression that I'm using right now is:
select REGEXP_SUBSTR(textfield,'CP\\?(?:\\d*:)*24658') as my_match
from table
where id = 1243;
Which at the moment returns just the first match:
CP?:24658
And I would like it to return all matches:
CP?:24658
CP?23432:24658
CP?:24658
Use just REGEXP to find the interesting rows. Put those into a temp table
Repeatedly process the temp table -- but remove the SUBSTR as you use it.
What will you be doing with each substr? Maybe that will help us devise a better approach.
i am bit confused by the nature and working of query , I tried to access database which contains each name more than once having same EMPid so when i accessed it in my DROP DOWN LIST then same repetition was in there too so i tried to remove repetition by putting DISTINCT in query but that didn't work but later i modified it another way and that worked but WHY THAT WORKED, I DON'T UNDERSTAND ?
QUERY THAT DIDN'T WORK
var names = (from n in DataContext.EmployeeAtds select n).Distinct();
QUERY THAT WORKED of which i don't know how ?
var names = (from n in DataContext.EmployeeAtds select new {n.EmplID, n.EmplName}).Distinct();
why 2nd worked exactly like i wanted (picking each name 1 time)
i'm using mvc 3 and linq to sql and i am newbie.
Both queries are different. I am explaining you both query in SQL that will help you in understanding both queries.
Your first query is:
var names = (from n in DataContext.EmployeeAtds select n).Distinct();
SQL:-
SELECT DISTINCT [t0].[EmplID], [t0].[EmplName], [t0].[Dept]
FROM [EmployeeAtd] AS [t0]
Your second query is:
(from n in EmployeeAtds select new {n.EmplID, n.EmplName}).Distinct()
SQL:-
SELECT DISTINCT [t0].[EmplID], [t0].[EmplName] FROM [EmployeeAtd] AS
[t0]
Now you can see SQL query for both queries. First query is showing that you are implementing Distinct on all columns of table but in second query you are implementing distinct only on required columns so it is giving you desired result.
As per Scott Allen's Explanation
var names = (from n in DataContext.EmployeeAtds select n).Distinct();
The docs for Distinct are clear – the method uses the default equality comparer to test for equality, and the default comparer sees 4 distinct object references. One way to get around this would be to use the overloaded version of Distinct that accepts a custom IEqualityComparer.
var names = (from n in DataContext.EmployeeAtds select new {n.EmplID, n.EmplName}).Distinct();
Turns out the C# compiler overrides Equals and GetHashCode for anonymous types. The implementation of the two overridden methods uses all the public properties on the type to compute an object's hash code and test for equality. If two objects of the same anonymous type have all the same values for their properties – the objects are equal. This is a safe strategy since anonymously typed objects are essentially immutable (all the properties are read-only).
Try this:
var names = DataContext.EmployeeAtds.Select(x => x.EmplName).Distinct().ToList();
Update:
var names = DataContext.EmployeeAtds
.GroupBy(x => x.EmplID)
.Select(g => new { EmplID = g.Key, EmplName = g.FirstOrDefault().EmplName })
.ToList();
"IN" query is not working. Please guide me if i am wrong.
KaizenResultsInformationTable is MasterTable having field "recordinfo", this field contains Child table Ids as string.
kaizenResultsRecordInformationTable is Childtable having field "recordId".
I have to match records of child.
Query:
select recordinfo from KaizenResultsInformationTable
Output: ;0;1;2;3;4;5;6;7;8;9;10
Query:
select substr(replace(recordinfo,';','","'),3,length(recordinfo))
from KaizenResultsInformationTable`
Output: "0","1","2","3","4","5"
This query is not working:
select * from kaizenResultsRecordInformationTable
where substr(recordid,0,2) in (
select substr(replace(recordinfo,';','","'),3,length(recordinfo))
from KaizenResultsInformationTable
)
This query is working:
select * from kaizenResultsRecordInformationTable
where substr(recordid,0,2) in ("0","1","2","3","4","5")
You can't use in like that. In your second query, you are passing in a single string containing a comma-separated list of values.
It is better to represent a list of IDs as one record for each value.
Also, I'm not sure why you are taking a substring of your recordid. You should usually be storing one value per column.
However, if you can't change the schema, you can use string matching with 'like' instead of 'in'. Something like this should work:
select a.* from kaizenResultsRecordInformationTable a
join KaizenResultsInformationTable b
on (';'+b.recordinfo+';') LIKE ('%;'+trim(substr(recordid,0,2))+';%')
So if your recordinfo looks like 1;2;3;4;5;6, and your substr(recordid,0,2) looks like 1, this will include that row if ";1;2;3;4;5;6;" LIKE "%;1;%", which is true.
I have got a datatable which contains many columns in which three are main:
hotelid
dshotelid
hotelname
Some hotels contain only dshotelid, some contains only hotelid and some contain both dshotelid and hotelid.
I need sort in such way so that those hotels who got both dshotelid and hotelid should be on top and then those hotels who have got only dshotelid and at last those hotels who have got only hotelid...
Please help me to create such a sort expression.
I created this :
dtmaintable.DefaultView.Sort = "dshotelid, hotelid"
but it Is not giving me desired output.
Fields with NULL in them tend to appear at the top of sorted columns (unless the sort is in descending order) so you're probably seeing rows with both hotelid and dshotelid at the bottom, instead of the top?
How is this data table populated? If it's coming from a database query, it's a simple matter to construct an additional column (or columns) which contain(s) whatever sort key you need - be it an amalgum of other columns or some other unique identifier.
EDIT: Feb 4, 2010 - in response to your 'FilterAndSortTable' solution:
Your solution works but it's not because of the FilterAndSortTable - it's because you used a different sort order.
Originally, you used "dsohtelid, hotelid".
The second time, you used "dshotelid desc, hotelid desc".
This has the effect of putting your non-nulls at the top and nulls at the bottom, but I would dispute that this qualifies as a good solution.
Your id's are now sorted backwards - which I kind of assumed you might want to avoid, hence my suggestion of a new sort column that would respect this.
Still, if the order of id's doesn't matter then your solution is fine and you can simply stick with your original code, with the addition of 'desc', like so:
dtmaintable.DefaultView.Sort = "dshotelid desc, hotelid desc"
Of course, if anything I've said here has been of any use to you, a tick would be muchly appreciated. It would help me reach 50 rep points and finally be able to write comments. :)
i got the answer its :
datagrid1.datasource = FilterandSortTable(dtmaintable,"", "dshotelid desc, hotelid desc")
Public Shared Function FilterandSortTable(ByVal SourceTable As DataTable, ByVal strFilters As String, Optional ByVal strOrder As String = "") As DataTable
Dim Tbl As DataTable = SourceTable.Clone
Dim rows() As DataRow = SourceTable.Select(strFilters, strOrder)
For i As Integer = 0 To rows.Length - 1
Tbl.ImportRow(rows(i))
Next
Return Tbl
End Function