Is there a way to include a blank row at the top of a sql query, eg if it is meant for a dropdown list? (MS Sql Server 2005 or 2008)
Select *
FROM datStatus
ORDER BY statusName
Where I want something like
-1 (please choose one)
1 Beginning
2 Middle
3 Ending
4 Canceled
From a table that is ordinarily just the above, but without the top row?
I feel it's nicer to do it outside SQL, but if you insist...
SELECT -1, '(please choose one)'
UNION
SELECT * FROM datStatus
ORDER BY statusName
I have found that it is better to do this in the presentation layer of your application, as you might have different requirements based on the context. In general I try to keep my data service layer free of these sorts of implementation specific rules. So in your case I would usually just add a new item by index in the first position of the list, after i had loaded it with data from my service layer.
Enjoy!
How about unioning the first row together with the rest of the query?
Select -1,'(please choose one)'
union all
select * FROM datStatus ORDER BY statusName
Related
I'm trying to understand more about SQL injection, so I found this lesson from Red Tiger Labs.
According to the solution, the cat=1 part of the URL is vulnerable to SQL injection.
I can understand that you can append ORDER BY X# and keep incrementing X to establish the number of columns, which is 4.
However according to the solution, the next step is to do:
cat=1 union select 1,2,3,4 from level1_users #
The table name is provided, so that's ok. But I'm really having trouble understanding the purpose of the UNION. My guess is the underlying code does something like:
SELECT * FROM level1_users where cat=1
Presumably it would expect only 0 or 1 results. Then it prints out some number of columns onto the screen. According to the example, it prints out:
This hackit is cool :)
My cats are sweet.
Miau
3
4
The first three lines were printed out without the extra SQL injection. So what's going on, and what's the significance?
I would not expect the union to do anything, I assume the numbers refer to columns?
So, I've managed to figure out what's going on here.
cat=1 union select 1,2,3,4 from level1_users #
The select part selects the numbers 1, 2, 3, 4 as columns. You could actually use anything here, like select 'cats', 'fish', 'bread', 42 and sometimes you have to do this as the union select must match the column types in the target table. The level1_users table is integers (or at least, integers work), hence selecting numbers.
I actually thought it might be selecting columns by their index, because often in sql you can do ORDER BY 1 for example to order by the first column, however that's not the case.
What tripped me up was that this particular SQL injection website dumps the entire contents of the result set to the screen, and I wasn't expecting that. If you think about it though it is looking for a category id and therefore it's not unreasonable to expect it to list everything in that category.
By performing a union it first shows that extra rows will be printed to the screen, and because we've numbered the columns, it shows which columns, columns 3 and 4.
From there it's possible to simply select username and password into those columns (you have to guess the table headers in this instance because although you can normally union onto the db data it has been disabled for this exercise).
is there any way within snowflake/sql query to view what tables are being queried the most as well as what columns? I want to know what data is of most value to my users and not sure how to do this programatically. Any thoughts are appreciated - thank you!
2021 update
The new ACCESS_HISTORY view has this information (in preview right now, enterprise edition).
For example, if you want to find the most used columns:
select obj.value:objectName::string objName
, col.value:columnName::string colName
, count(*) uses
, min(query_start_time) since
, max(query_start_time) until
from snowflake.account_usage.access_history
, table(flatten(direct_objects_accessed)) obj
, table(flatten(obj.value:columns)) col
group by 1, 2
order by uses desc
Ref: https://docs.snowflake.com/en/sql-reference/account-usage/access_history.html
2020 answer
The best I found (for now):
For any given query, you can find what tables are scanned through looking at the plan generated for it:
SELECT *, "objects"
FROM TABLE(EXPLAIN_JSON(SYSTEM$EXPLAIN_PLAN_JSON('SELECT * FROM a.b.any_table_or_view')))
WHERE "operation"='TableScan'
You can find all of your previous ran queries too:
select QUERY_TEXT
from table(information_schema.query_history())
So the natural next step would be combine both - but that's not straightforward, as you'll get an error like:
SQL compilation error: argument 1 to function EXPLAIN_JSON needs to be constant, found 'SYSTEM$EXPLAIN_PLAN_JSON('SELECT * FROM a.b.c')'
The solution would be to combine the queries from the query_history() with the SYSTEM$EXPLAIN_PLAN_JSON outside (to make the strings constant), and then you will be able to find out the most queried tables.
I'm trying to query my database to pull only duplicate/old data to write to a scratch section in excel (Using a macro passing SQL to the DB).
For now, I'm currently testing in Access alone to only filter out the old data.
First, I'm trying to filter my database by a specifed WorkOrder, RunNumber, and Row.
The code below only filters by Work Order, RunNumber, and Row. ...but SQL doesn't like when I tack on a 2nd AND statement; so this currently isn't working.
SELECT *
FROM DataPoints
WHERE (((DataPoints.[WorkOrder])=[WO2]) AND ((DataPoints.[RunNumber])=6) AND ((DataPoints.[Row]=1)
Once I figure that portion out....
Then if there is only 1 entry with specified WorkOrder, RunNumber, and Row, then I want filter it out. (its not needed in the scratch section, because its data is already written to the main section of my report)
If there are 2 or more entries with said criteria(WO, RN, and Row), then I want to filter out the newest entry based on RunDate and RunTime, and only keep all older entries.
For instance, in the clip below. The only item remaining in my filtered query will be the top entry with the timestamp 11:47:00AM.
.
Are there any recommended commands to complete this problem? Any ideas are helpful. Thank you.
I would suggest something along the lines of the following:
select t.*
from datapoints t
where
t.workorder = [WO2] and
t.runnumber = 6 and
t.row = 1 and
exists
(
select 1
from datapoints u
where
u.workorder = t.workorder and
u.runnumber = t.runnumber and
u.row = t.row and
(u.rundate > t.rundate or (u.rundate = t.rundate and u.runtime > t.runtime))
)
Here, if the correlated subquery within the where clause finds a record with the same workorder, runnumber and row, but with either a later rundate or the same rundate and a later runtime, then the record is returned by the main query.
You need two more )'s at the end of your code snippet. Or you can delete the parentheses completely in this example, MS Access will ad them back in as it deems necessary.
M.S. Access SQL can be tricky as it is not standards compliant and either doesn't allow for super complex queries, or it needs an ugly work around, like having a parentheses nesting nightmare when trying to join more than two tables.
For these reasons, I suggest using multiple Access queries to produce your results.
I am wondering if it's possible to use a view to get the top 5 lines from a table.
I am finding that Crystal reports doesn't seem to have anything built in to do this, or I'd do it there.
When I query the view Select * from qryTranHistory, it returns the first 5 items, but if I try to select a specific type Select * from qryTranHistory Where tID = 45 it returns nothing, since there are no tID=45 in the top 5 normally.
Is it possible to do this?
Can it be accomplished in a sub report in Crystal Reports?
It is easy to limit a report to the top 5 records. In the menu, just choose
Report --> Selection Formulas... --> Group
In the formula, enter "RecordNumber <= 5" and you are done.
You don't need to have a group field nor summary field to do the group filter. You don't need a sort order, but using top N records without a sort order doesn't usually make much sense. It might not be efficient as OMG Ponies suggested, but for small number of records it is OK.
You can reference a sproc from Crystal Reports. In the sproc, use a conditional on the parameter.
ALTER PROCEDURE dbo.Get_TOP5
(
#tID INT = NULL
)
AS
IF #tID IS NULL
BEGIN
SELECT TOP 5
FIELD1,
FIELD2
FROM qryTranHistory
END
ELSE
BEGIN
SELECT
FIELD1,
FIELD2
FROM qryTranHistory
WHERE tID =#tID
END
A simple setting can limit the records to top 5!! Here it is, if you're using .Net 1.1 (similar arrangement of options in higher frameworks too!).
Right click on the report layout > Reports > Top N/Sort Group Expert > Choose Top N in the Dropdown that asks for the type of filtering/ sorting you wish to do > Set the Value of top N (5 in your case) > Uncheck the option that includes other records.
Your report will be filtered for only the top 5 records from the Dataset.
There's another way how it could be done and that is through the Record selection formula where you limit the No. of records, as suggested by John Price in this thread.
Cheers!
Can you put the TOP in your SELECT statement instead of in the view?
SELECT TOP 5
col1,
col2,
...
FROM
qryTranHistory
WHERE
tid = 45
If your table has more then 5 rows I hope this query:
SELECT * FROM qryTranHistory
Returns more then 5 rows because you never mentioned TOP 5.
Your question doesn't make a lot of sense as I am not sure waht you are after.
You mentioned if you ran your query with WHERE tID=45, it returns nothing, what exactly do you want it to return ?
Read up on TOP in BOL:
SELECT TOP 10 Recs FROM Records WHERE...
By the way you do not want to do this in the report / a form interface, you want to do this in your db layer.
You can do Top N processing in Crystal Reports, but it's a little obscure - you have to use the group sort expert (and in order to use that, you need to have groups and summary fields inserted into the groups.)
Doing the Top N processing in the query should be more efficient, where possible.
If you have a small recordset, you can create a running total that counts the change of rows (field1), then in Section Expert in Details, tell it to supress RTotal0 (your running total variable) to > 5
I am selecting from a database of news articles, and I'd prefer to do it all in one query if possible. In the results, I need a sorting criteria that applies ONLY to the first result.
In my case, the first result must have an image, but the others should be sorted without caring about their image status.
Is this something I can do with some sort of conditionals or user variables in a MySQL query?
Even if you manage to find a query that looks like one query, it is going to be logicaly two queries. Have a look at MySQL UNION if you really must make it one query (but it will still be 2 logical queries). You can union the image in the first with a limit of 1 and the rest in the second.
Something like this ensures an article with an image on the top.
SELECT
id,
title,
newsdate,
article
FROM
news
ORDER BY
CASE WHEN HasImage = 'Y' THEN 0 ELSE 1 END,
newsdate DESC
Unless you define "the first result" closer, of course. This query prefers articles with images, articles without will appear at the end.
Another variant (thanks to le dorfier, who deleted his answer for some reason) would be this:
SELECT
id,
title,
newsdate,
article
FROM
news
ORDER BY
CASE WHEN id = (
SELECT MIN(id) FROM news WHERE HasImage = 'Y'
) THEN 0 ELSE 1 END,
newsdate DESC
This sorts the earliest (assuming MIN(id) means "earliest") article with an image to the top.
I don't think it's possible, as it's effectively 2 queries (the first query the table has to get sorted for, and the second unordered), so you might as well use 2 queries with a LIMIT 1 in the first.