- SQL query with a sort performed in the query editor
- SQL query with sort through programming
How to sort the result of a query?
To sort (or classify) the records coming from a data file, you have the ability to perform a browse loop on the file by using a key item. In this case, the classifying will be perfomed on the key items only. The best method to perform this sort (or classifying) consists in using an SQL query. Let's see how to perform a sort by using: SQL query with a sort performed in the query editor The query is used to sort (classify) the records found in a data file according to an item. In this example, we are going to create an SQL query used to sort the records found in CUSTOMER file according to the customer name. The different steps for creating this SQL query with sort are as follows: - Click
 in the quick access buttons. - In the window that is displayed, click "Queries".
- The query creation wizard starts.
- Specify that you want to create a select query ("Select" option).
Go to the next step of the wizard. - The query description window appears.
- Give a name and a caption to the query:
- In the left section of the description window, choose the file items that will be used. In our example, we are going to select the CustomerName, Company, ZipCode and City items from the CUSTOMER file.
- Double-click the names of the items to add them to the list of query items:
- To perform a sort, select the item to sort in the middle section. In our example, this item corresponds to "CustomerName".
- In the right section of the editor, click the "Sort" button.
- Select "Sort by the selected item" from the menu that is displayed. The following window appears:
- Select the sort order (ascending in our example).
- Validate. The query description window is updated: an arrow with the sort number is displayed.
- Validate the query description window. The query is displayed in the editor:
- Save the query (Ctrl + S).
- Press F2 to see the SQL code:
- Run the query test (GO in the quick access buttons).
- The query can be run in the program by HExecuteQuery.
SQL query with sort through programming The SQL queries can be directly written through programming in the WLanguage code. To do so, you must: - Create a variable of type Data source to represent the query at runtime.
- Create a Character String variable to contain the SQL code of the query and write the SQL code in this variable.
- Run the SQL query with HExecuteSQLQuery.
- Browse the result with the HReadXXX functions.
Code sample:
Src1 is Data Source
sSQLCode is string
// List of orders sorted by descending Date and Time ...
sSQLCode = [
SELECT ORDERS.OrderNum,
ORDER.ORDDATE,
ORDER.ORDTime
FROM ORDERS
ORDER BY ORDDATE DESC, ORDTime DESC
]
HExecuteSQLQuery(Src1, hQueryDefault, sSQLCode)
FOR EACH Src1
Trace(Src1.OrderNum, Src1.ORDDATE, Src1.ORDTime)
END
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