Trying to build a dashboard using Oracle's Brio. I have to access 6 different databases to grab the same type of data, aggregate it and display it. Except that when I do it, Brio grabs the data from the first source just fine. When I grab the data from the second data source, Brio replaces the original data with the second set. So I am not able to aggregate the data. Can anyone help me figure out how I can do this in Brio please?
You need to use a UNION statement, rather than running the query 6 times.
For example:
Don't do this
SELECT * FROM DATABASE_1..TABLE_1
GO
SELECT * FROM DATABASE_2..TABLE_1
GO
SELECT * FROM DATABASE_3..TABLE_1
GO
Do this instead
SELECT * FROM DATABASE_1..TABLE_1
UNION
SELECT * FROM DATABASE_2..TABLE_1
UNION
SELECT * FROM DATABASE_3..TABLE_1
GO
If you're using different OCE files for each source -- as you probably are -- then there's no easy way to do this. You'll need a separate query for each OCE file
If all your databases can be found under one OCE file, you can use the UNION trick; more to point, in Brio it's found as "Append Query". Just make sure you build the query identically to the first query in terms of what it returns; all the column headings will be from it.
If you need to consolidate the different queries into a single results section, the easiest -- well, only -- way that I've found to do it using only standard Brio functions is to join each set through a full outer join on every field and then coalesce each field together ... but this is horribly inefficient and will not finish for larger files. You'd probably be better off sorting the files and writing a javascript routine to parse them together, or doing the whole thing outside of Brio in the first place.
Related
Given a SELECT statement in Big Query and the Java SDK, what are my options to get the actual column names without fetching the data? I know I can execute the statement and then get the Schema via the TableResult. But is there a way to get the names without fetching data? We have a tool where we run arbitrary queries which are not known upfront and in my code I want to access the result columns by name.
Update: someone flagged this as duplicate of a 7 year old entry. I am however looking for a way to use the Java SDK alone to get the column names, not to do some magic with the query itself or query some metatable.
There are few options but the easiest is to add limit 0 to your query so for example:
SELECT * FROM projectId.datasetId.tableId limit 0
As of now, Hive Terminal is showing only column headers after a create table code is run. What settings should I change to make Hive Terminal show few rows also, say first 100 rows?
Code I am using to create table t2 from table t1 which resides in the database (I don't know how t1 is created):
create table t2 as
select *
from t1
limit 100;
Now while development, I am writing select * from t2 limit 100; after each create table section to get the rows with headers.
You cannot
The Hive Create Table documentation does not mention anything about showing records. This, combined with my experience in Hive makes me quite confident that you cannot achieve this by mere regular config changes.
Of course you could tap into the code of hive itself, but that is not something to be attempted lightly.
And you should not want to
Changing the create command could lead to all kinds of problems. Especially because unlike the select command, it is in fact an operation on metadata, followed by an insert. Both of these normally would not show you anything.
If you would create a huge table, it would be problematic to show everything. If you choose always to just show the first 100 rows, that would be inconsistent.
There are ways
Now, there are some things you could do:
Change hive itself (not easy, probably not desirable)
Do it in 2 steps (what you currently do)
Write a wrapper:
If you want to automate things and don't like code duplication, you can look into writing a small wrapper function to call the create and select based on just the input of source (and limit) and destination.
This kind of wrapper could be written in bash, python, or whatever you choose.
However, note that if you like executing the commands ad-hoc/manually this may not be suitable, as you will need to start a hive JVM each time you run such a program and thus response time is expected to be slow.
All in all you are probably best off just doing the create first and select second.
The below command mentioned seems to be correct to show the first 100 rows:
select * from <created_table> limit 100;
Paste the code you have written to create the table will help to diagnose the issue in hand!!
Nevertheless , check if you have correctly mentioned the delimiters for the elements, key-value pairs, collection items etc while creating the table.
If you have not defined them correctly you might end up with having only the first row(header) being shown.
I ran into a strange behaviour within Access. I basically have two predefined queries within my VBA-Project that are needed in different parts of the programm which are working fine.
Now I need a query which returns both result-sets as one. So my go to Solution was to create a new query combining the other two queries. Just like:
SELECT * FROM query1
UNION
SELECT * FROM query2;
Both queries have the same layout in their result. But if the result of query1 is empty and query2 has some records in its result I receive an empty result from the code above. The other way (empty result for query2 - several results for query1) it is delivering me a complete result.
I also tested the above code with the two queries switched. But the behaviour was the same. Same thing with UNION ALL.
What could be the issue here?
Edit: So, I did some further testing. The reason seems to be within query2. It can't even be unionized with itself. So if i try:
SELECT * FROM query2
UNION ALL
SELECT * FROM query2;
I again get an empty set. Same when i just use one field in the SELECT-part.
Edit2: OK it gets better. The Dataset is empty but within the table-view of the query result i have all the data within the filters of the columns. But if I do a Count(rowname) I get a 0 in return.
After two days of testing I was fed up and moved the code to another machine. Worked there. So after exporting it on the new machine and transferring it to my PC everything was functioning as it should. So I guess it was a problem related to the frontend I was using.
So if you run into smth. similar make sure that your project isn't corrupted in any way. (even if there aren't any errors shown by Access)
I am doing a simple SELECT statement in an Oracle DB and need to select the columns in a somewhat-specific order. Example:
Table A has 100 attributes, one of which is "chapter" that occurs somewhere in the order of columns in the table. I need to select the data with "chapter" first and the remaining columns after in no particular order. Essentially, my statement needs to read something like:
SELECT a.chapter, a. *the remaining columns* FROM A
Furthermore, I cannot simply type:
SELECT a.chapter, a.*
because this will select "chapter" twice.
I know the SQL statement seems simple, but if I know how to solve this problem, I can extrapolate this thought into more complicated areas. Also, let's assume that I can't just scroll over to find the "chapter" column and drag it to the beginning.
Thanks.
You should not select * in a program. As your schema evolves it will bring in things you do not know yet. Think about what happens when someone add a column with the whole book in it? The query you thought would be very cheap suddenly starts to bring in megabytes of data.
That means you have to specify every column you need.
Your best bet is just to select each column explicitly.
A quickie way to get around this would be SELECT a.chapter AS chapterCol, a.* FROM table a; This means there will be one column name chapterCol (assuming there's not a column already there named chapterCol. ;))
If your going to embed the 'SELECT *' into program code, then I would strongly recommend against doing that. As noted by the previous authors, your setting up the code to break if a column is ever added to (or removed from) the table. The simple advice is don't do it.
If your using this in development tools (viewing the data, and the like). Then, I'd recommend creating a view with the specific column order you need. Capture the output from 'SELECT COLUMN_NAME FROM ALL_TAB_COLUMNS' and create a select statement for the view with the column order you need.
This is how I would build your query without having to type all the names in, but with some manual effort.
Start with "Select a.chapter"
Now perform another select on your data base as follows :
select ','|| column_name
from user_tab_cols
where table_name = your_real_table_name
and column_name <> 'CHAPTER';
now take the output from that, in a cut-and-paste manner and append it to what you started with. Now run that query. It should be what you asked for.
Ta-da!
Unless you have a very good reason to do so, you should not use SELECT * in queries. It will break your application every time the schema changes.
I have 150+ SQL queries in separate text files that I need to analyze (just the actual SQL code, not the data results) in order to identify all column names and table names used. Preferably with the number of times each column and table makes an appearance. Writing a brand new SQL parsing program is trickier than is seems, with nested SELECT statements and the like.
There has to be a program, or code out there that does this (or something close to this), but I have not found it.
I actually ended up using a tool called
SQL Pretty Printer. You can purchase a desktop version, but I just used the free online application. Just copy the query into the text box, set the Output to "List DB Object" and click the Format SQL button.
It work great using around 150 different (and complex) SQL queries.
How about using the Execution Plan report in MS SQLServer? You can save this to an xml file which can then be parsed.
You may want to looking to something like this:
JSqlParser
which uses JavaCC to parse and return the query string as an object graph. I've never used it, so I can't vouch for its quality.
If you're application needs to do it, and has access to a database that has the tables etc, you could run something like:
SELECT TOP 0 * FROM MY_TABLE
Using ADO.NET. This would give you a DataTable instance for which you could query the columns and their attributes.
Please go with antlr... Write a grammar n follow the steps..which is given in antlr site..eventually you will get AST(abstract syntax tree). For the given query... we can traverse through this and bring all table ,column which is present in the query..
In DB2 you can append your query with something such as the following, but 1 is the minimum you can specify; it will throw an error if you try to specify 0:
FETCH FIRST 1 ROW ONLY