I am sure this is as simple as a question can get but I have been stumped on it so figured that I would ask in hope of a quick response. Using an OLEDB connection I want to do a select statement but for the table I am selecting from, a table member also has to be there too which seems to be messing up my results.
Normally I would write to get the column "col1":
SELECT lib1.table.col1 FROM lib1.table
For the table I need the information from, the table has a "submember". From what I have gathered the syntax is something like this:
SELECT lib1.table(submember).col1 FROM lib1.table(submember)
The problem is that the results are giving me every column within the table, not just my "col1" data. I hope that this is well explained for what I am looking for. Thanks ahead of time for anyone who helps.
You should be able to create an ALIAS in QTEMP:
CREATE ALIAS QTEMP.TABLE FOR LIB1.TABLE (SUBMEMBER)
And then query through the temporarily created alias:
SELECT COL1 FROM QTEMP.TABLE
It will be automatically removed when your connection ends.
create alias library.aliasname for library.table(member)
Then do the select on the alias
Related
Halo,
first, i say thank you for helping me solve my problem before.
I'm really newbie using Postgresql.
now i have new problem,
i do select statement like this one :
select * from company where id=10;
when i see the query in pg_stat_statements, i just get the query like this :
select * from company where id=?;
from the result the value of id is missing,
how i can get the complete query without missing the value??
Thank you :)
Alternatively you could set log_min_duration to 0 which will lead Postgres to log every statement.
Pg_stat_statements is meant to be for stats and these are aggregated, if every lookup value would be in there the stats would be useless because it would be hard to group.
If you want to understand a query just run it with explain analyze and you will get the query plan.
I have some tables by day and by hour, called 2015_09_01_00, 2015_09_01_01..., 2015_09_02_00, 2015_09_02_01, etc.
I also created a virtual table for 2015_09_01, 2015_09_02, etc, aggregating them respectively by day.
So, in this context, when I want to query some virtual tables (some days) I have to execute this query for example:
SELECT fields FROM TABLE_QUERY(dataset, 'REGEXP_MATCH(table_id, r"(2015_09_01|2015_09_02)$")')
It gives network unreachable error, I guess is messing up between the original tables and the virtual ones since the names are related.
However, if I execute:
SELECT table_id FROM dataset.__TABLES_SUMMARY__ WHERE REGEXP_MATCH(table_id, r"(2015_09_01|2015_09_02)$")
2015_09_01
2015_09_02
it seems that the filter is created successfully.
So, what am I doing wrong here?
Thanks for your help in advance.
Above example worked for me.
Most likely in your dataset you have other tables with same pattern as you are trying to match.
Try to restrict your regex. For example as below
SELECT fields FROM TABLE_QUERY(dataset, 'REGEXP_MATCH(table_id, r"^(2015_09_01|2015_09_02)$")')
Did you define the daily views to reference themselves? Your use of $ suggested you were thinking about this, but to make sure -- they should reference only the hourly tables.
For example, if you named a view 2014_09_14 when it was based on a TABLE_QUERY for
'REGEXP_MATCH(table_id, r"2015_09_14")'
then it would reference itself, which does not work. (This ought to be a clearer error though.)
If you define the view with a TABLE_QUERY that can't match itself
'REGEXP_MATCH(table_id, r"2015_09_14_\d\d")'
then it should work. If you select your view's "Details" what is the query that defined it?
Just inherited an Access database and trying to figure some things out. For the life of me, I have no idea what this query means.
SELECT [col1]/[col2].[col3]...
Its like the [col1]/[col2] is the table name and [col3] is the column. But instead of a table, it is math function (dividing two columns) followed by the column name. SELECT table.column....
I thought this might be inherent to someone with Access experience (or maybe this is some SQL that I am not familiar with). If it is not just comment and I will post all of the info.
SELECT [coly]/[table].[colx]...
I'm building an abstract gem. i need a sql query that looks like this
SELECT * FROM my_table WHERE * LIKE '%my_search%'
is that possible?
edit:
I don't care about querys performance because it's a feature function of a admin panel, which is used once a month. I also don't know what columns the table has because it's so abstract. Sure i could use some rails ActiveRecord functions to find all the columns but i hoped to avoid adding this logic and just using the *. It's going to be a gem, and i can't know what db is going to be used with it. Maybe there is a sexy rails function that helps me out here.
As I understand the question, basically you are trying to build a sql statement which should check for a condition across all columns in that table. A dirty hack, but this generates the required Sql.
condition_string = MyTable.column_names.join(' LIKE ? OR ')
MyTable.all(:conditions => [condition_string, '%my_search%'])
However, this is not tested. This might work.
* LIKE '...' isn't valid according to the SQL standards, and not supported by any RDBMS I'm aware of. You could try using a function like CONCAT to make the left argument of LIKE, though performance won't be good. As for SELECT *, it's generally something to be avoided.
No, SQL does not support that syntax.
To search all columns you need to use procedures or dynamic SQL. Here's another SO question which may help:
SQL: search for a string in every varchar column in a database
EDIT: Sorry, the question I linked to is looking for a field name, not the data, but it might help you write some dynamically SQL to build the query you need.
You didn't say which database you are using, as there might be a vendor specific solution.
Its only an Idea, but i think it worth testing!
It depends on your DB you can get all Columns of a table, in MSSQL for example you can use somethink like:
select name from syscolumns where id=object_id('Tablename')
Under Oracle guess its like:
select column_name from USER_TAB_COLUMNS where TABLE_NAME = 'Tablename'
and then you will have to go through these columns usign a procedure and maby a cursor so you can check for each Column if the data your searching for is in there:
if ((select count(*) from Tablename where Colname = 'searchingdata') > 0)
then keep the results in a separated table(ColnameWhereFound, RecNrWhereFound).
The matter of Datatye may be an Issue if you try to compare strings with numbers, but if you notice for instance under SQL-Server the syscolumns table contains a column called "usertype" which contains a number seems to refer to the Datatype stored in the Columne, like 2 means string and 7 means int, and 2 means smallint, guess Oracle would have something similar too.
Hope this helps.
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.