i need your help to finish my delphi homework.
I use ms access database and show all data in 1 dbgrid using sql. I want to show same column but with criteria (50 record per column)
i want select query to produce output like:
No | Name | No | Name |
1 | A | 51 | AA |
2 | B | 52 | BB |
3~50 | | 53~100| |
Is it possible ?
I can foresee issues if you choose to return a dataset with duplicate column names. To fix this, you must change your query to enforce strictly unique column names, using as. For example...
select A.No as No, A.Name as Name, B.No as No2, B.Name as Name2 from TableA A
join TableB B on B.Something = A.Something
Just as a note, if you're using a TDBGrid, you can customize the column titles. Right-click on the grid control in design-time and select Columns Editor... and a Collection window will appear. When adding a column, link it to a FieldName and then assign a value to Title.Caption. This will also require that you set up all columns. When you don't define any columns here, it automatically returns all columns in the query.
On the other hand, a SQL query may contain duplicate field names in the output, depending on how you structure the query. I know this is possible in SQL Server, but I'm not sure about MS Access. In any case, I recommend always returning a dataset with unique column names and then customizing the DB Grid's column titles. After all, it is also possible to connect to an excel spreadsheet, which can very likely have identical column names. The problem arrives when you try to read from one of those columns for another use.
Related
i have a table in sql which is like this:
| product code | weight|
| ----------------------|-----------|
| 1235896 | 0.5|
| 3256kms | 1.5|
| dk-kmsw | 3 |
and the data type for [product code] is nvarchar
now i want to call the weight by putting the product code in processmaker
the code that i wrote is this:
select [weight] from table where [product code] = ##textVar047
and by this code i get nothing, i have changed the ## to ##, #= but it did not work.
how can i do this?
any comment is appreciated.
When you use ## in the SQL of a control, it means you are referencing another control's value. If that's your scenario I'd suggest first to retrieve the full list of product codes in a Suggest control (instead of a Textbox) with this SQL:
select PRODUCT_CODE, PRODUCT_CODE FROM YOUR_TABLE_NAME
(you call product code twice since Suggest controls, like dropdowns, need 2 values to be filled up, one for the id and one for the label)
Now that you have a way to obtain the actual code and it's saved in the suggest control id, you can make another field a dependent field with the SQL you where proposing:
select WEIGHT FROM YOUR_TABLE_NAME where PRODUCT_CODE = ##your_suggest_control_id
(## should work just fine as it just adds quotes to the variable)
You can also check the wiki page to get an in depth explanation of this. https://wiki.processmaker.com/3.1/Dependent_Fields
I hope this helps!
select CAST(weight AS nvarchar(max)) from table where [product code] = ##textVar047
When I try to join on one of the customDimensions fields, I get a syntax error: "join attributes may be only column entity or equality expressions". I am able to join on non-custom columns such as name or timestamp.
Sample code:
let ExperimentLaunchedEvents = customEvents | where name=="ExperimentLaunched" and timestamp > now(-30d);
let ExperimentTerminatedEvents = customEvents | where name=="ExperimentTerminated" and timestamp > now(-30d);
ExperimentLaunchedEvents
| project name, timestamp, experimentId=customDimensions.ExperimentId
| join kind=leftanti (ExperimentTerminatedEvents
| project name, timestamp, experimentId=customDimensions.ExperimentId) on tostring(experimentId)
If joining on customDimensions columns is not supported, is there any way to achieve selecting launched experiments that haven't been terminated? Thanks!
As mentioned by John in the comments When using custom dimensions for any operations you need to convert it to a type that can be used by the query engine. In this case I use tostring(), but you can also use other functions like toint().
I also extend a column type so it can be reused in clauses like join or where without having to use the long hand over and over again.
ExperimentLaunchedEvents
| extend experimentId=tostring(customDimensions.ExperimentId)
| project name, timestamp, experimentId
| join kind=leftanti (ExperimentTerminatedEvents
| extend experimentId=tostring(customDimensions.ExperimentId)
| project name, timestamp, experimentId)
on experimentId
Same as James Davis answer, but a minor enhancement of stopping the experimentId column repeating twice due to its inclusion in both the project clauses, as pointed out by squallsv
let myExperimentLauncedEvents=
ExperimentLaunchedEvents
| extend experimentId=tostring(customDimensions.ExperimentId)
| project name, timestamp, experimentId
| join kind=leftanti (ExperimentTerminatedEvents
| extend experimentId=tostring(customDimensions.ExperimentId)
| project name, timestamp, experimentId)
on experimentId;
myExperimentLauncedEvents
| project name, timestamp, experimentId
As a result, by assigning the result to a variable (temp table), and then using the project clause on that variable, we can choose to display only those columns that are required.
How can I merge two or three tables into one single table and make a big master table in QlikView?
Scenario : I have following 3 Tables. They all contain different facts but i want to merge them and make a big fact table.
(Table#1) Order_Case
OrderID | CaseID | CustomerID | WorkFlowID
(Table#2) Work_Flow
WorkFlowID | WorkFlowStatus | CreatedDate |
(Table#3) Product_Detail
CaseID | ProductID | SupplierID |
What I am trying to achieve : is I want to merge all this tables into a single table so the matching field data should merge and if the field does not match then it should show NULL against it.
This should work just fine, if its not, than you have a problem in one of the "key/join" fields:
Load OrderID ,CaseID,CustomerID,WorkFlowID resident Table#1;
join // or left join
Load WorkFlowID,WorkFlowStatus,CreatedDate resident Table#2;
join
load CaseID,ProductID,SupplierID resident Table#3;
You don't need those merging... as long you have the same Field Name
(as I noticed)
Order_case will be connected to Work_flow by field WorkflowID
and
Order_case will also be connected to Product_Detail by field CaseID
You just need to LOAD them in sequence (all three)
These are star-scheme fact tables, it is quite common and applicable in qlikview, you'll just need to "play along" with the filtering
Hope this can help...
I am using Ruby on Rails 4 and MySQL. I have three types. One is Biology, one is Chemistry, and another is Physics. Each type has unique fields. So I created three tables in database, each with unique column names. However, the unique column names may not be known before hand. It will be required for the user to create the column names associated with each type. I don't want to create a serialized hash, because that can become messy. I notice some other systems enable users to create user-defined columns named like column1, column2, etc.
How can I achieve these custom columns in Ruby on Rails and MySQL and still maintain all the ActiveRecord capabilities, e.g. validation, etc?
Well you don't have much options, your best solution is using NO SQL database (at least for those classes).
Lets see how can you work around using SQL. You can have a base Course model with a has_many :attributes association. In which a attribute is just a combination of a key and a value.
# attributes table
| id | key | value |
| 10 | "column1" | "value" |
| 11 | "column1" | "value" |
| 12 | "column1" | "value" |
Its going to be difficult to determin datatypes and queries covering multiple attributes at the same time.
Sorry, I am very new to DbGrids.
Should I use the query's field editor and somehow add a new field that captures the TIMEDIFF and then just add that as a column in my DbGrid?
Or can/should I skip the field editor and somehow declare the TIMEDIFFF as a column?
For this table, I want a DbGrid with 4 columns : start time, end time, duration, description (run_id is the primary key & will not be displayed).
I am stumped as to how to get data into a 'duration' column ...
mysql> describe test_runs;
+------------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------------+-------------+------+-----+---------+----------------+
| run_id | int(11) | NO | PRI | NULL | auto_increment |
| start_time_stamp | timestamp | YES | | NULL | |
| end_time_stamp | timestamp | YES | | NULL | |
| description | varchar(64) | YES | | NULL | |
+------------------+-------------+------+-----+---------+----------------+
4 rows in set (0.37 sec)
[Update]
The query for the datasource is
SELECT start_time_stamp,
end_time_stamp,
TIMEDIFF(end_time_stamp, start_time_stamp) as duration,
description
FROM test_runs ORDER BY start_time_stamp DESC
and when I execute it manually in MySql, I get
mysql> select TIMEDIFF(end_time_stamp, start_time_stamp) as duration FROM
+----------+
| duration |
+----------+
| NULL |
| 00:04:43 |
| 00:00:13 |
| 00:00:06 |
| 00:00:04 |
+----------+
5 rows in set (0.00 sec)
but the corresponding column in the DB grid remains blank. Can anyone help? Thanks.
[Update] I am using AnyDac, if that helps. The query produces all fields, including the time difference, in MySql and also in the Delphi IDE when I use the AnYDac query editor and execute it.
The only problem is that I don't see it in the DB grid at run time. I double click the DB grid at design time and the columns are correct. The FielName property is set to duration, which is retuned by the query shown above. It doesn't exist in the database, but is calculated by the query; could that somehow be the problem??
[Aaaaaaaargh!!!] Someone tried to "improve" my code and set the query's text programatically at run-time (as SELECT * FROM test_runs), thus overwriting my design time query!! Since the databse table does not have a duration field, none was shown in the DB grid.
Words were had, voices were rasied and now I must apolgize for wasting your time. Sorry.
I would create a calculated field in your Query and add that field to your DbGrid.
so, as you say, with the Field Editor open for the query, right-click and select New Field (or press Ctrl-N). Give your new field a name (eg Duration), keep Component name default or rename if you desire. Set the Type as appropriate (DateTime most likely in this case) and set the Field Type to Calculated.
Then, in the OnCalcFields event of your Query, set the value of that field to the value you want. eg:
procedure TForm1.Query1CalcFields(DataSet: TDataSet);
begin
Dataset.FieldByName('description').AsDateTime :=
DataSet.FieldByName('end_time_stamp').AsDateTime -
DataSet.FieldByName('start_time_stamp').AsDateTime;
end;
Or, you could also include the Duration as an extra field in your select query. Unfortunately I don't have ready access to MySQL here, but it could be something like:
select run_id, start_time_stamp, end_time_stamp, description,
(end_time_stamp - start_time_stamp) as duration from test_runs;
Should I use the query's field editor and somehow add a new field that
captures the TIMEDIFF and then just add that as a column in my DbGrid?
Not at first, delete all of the entries from that field editor
Or can/should I skip the field editor and somehow declare the
TIMEDIFFF as a column?
Not at first, delete all of the entries from that column editor
After that you should see all columns from the open dataset inside the grid, because you eliminate all the limitations from column editor and field editor.
As a guess what happens to your grid/data you did not set the FieldName property for column duration and therefor the grid didn't know what to present.
to use a DBgrid you need a datasource,dataset each should be assigned to respective components,and make sure you have made the connection. if you didnt get any thing in the grid you need to check your dataset,if only the date difference column data is missing but header display the field name in the query then probably you may be getting null data.....if even you didn't get the header name too you need to check your query.......