- Overview
- Overload a WLanguage function
- Overview
- How to overload a WLanguage function?
- Differentiating between the WLanguage function and the custom function
- Using WLanguage functions in the SQL queries for HFSQL
- Overview
- How to proceed?
- Remarks
Overloading a WLanguage function or using a WLanguage function in an SQL query
 Available only with these kinds of connection
WLanguage proposes the " WL." keyword to: - Overload a WLanguage function.
- Use a WLanguage function in an SQL query run by the HFSQL engine.
Versions 22 and laterRemark: The " WL." keyword also allows you to use a WLanguage constant in an SQL query containing a WLanguage function. New in version 22Remark: The " WL." keyword also allows you to use a WLanguage constant in an SQL query containing a WLanguage function. Remark: The "WL." keyword also allows you to use a WLanguage constant in an SQL query containing a WLanguage function.
Remark: From version 19, HFSQL is the new name of HyperFileSQL. Overload a WLanguage function Using WLanguage functions in the SQL queries for HFSQL Overview A WLanguage function can be used in an SQL query. This SQL query can be run on HFSQL files. You can for example use the WLanguage functions to create advanced selection conditions. The WLanguage functions can be used in the SQL code of a query or in the query editor (for example, when creating a calculation item that is using a mathematical formula). How to proceed? To use WLanguage functions in the queries for HFSQL: - Create a query in the query editor.
- To use the WLanguage functions in the query, use the following notation: WL.<Function name>
The WLanguage functions can be used for example:- In the SQL code of the query. Example:
SELECT Task.Caption FROM Task WHERE
WL.DateDifference(Task.StartDate, Task.EndDate) > 5
- In a mathematical formula handled by a calculated item.
- The query can be:
Remarks - Only the WLanguage functions can be used in the queries. The properties cannot be used.
- Several WLanguage functions can be nested in a query.
- If the WLanguage functions is used in SELECT, the returned value is a text memo.
- This syntax can only be used with HFSQL Classic, Mobile and Client/Server.
- The limits of the WLanguage function are identical if the function is used in a query.
- The following functions are available in the queries:
- To use Open, OpenChild and OpenPopup in the queries, the name of windows must be passed in character string format (between quotes).
Versions 22 and laterTo use a WLanguage constant in the queries containing WLanguage functions, use the following notation: WL.<Constant name> For example, SQL code of query:
SELECT
WL.ExtractString('A|B|C',1,'|'),
WL.ExtractString('A|B|C',1,'|', WL.FromEnd)
FROM
DUAL
New in version 22To use a WLanguage constant in the queries containing WLanguage functions, use the following notation: WL.<Constant name> For example, SQL code of query:
SELECT
WL.ExtractString('A|B|C',1,'|'),
WL.ExtractString('A|B|C',1,'|', WL.FromEnd)
FROM
DUAL
To use a WLanguage constant in the queries containing WLanguage functions, use the following notation: WL.<Constant name> For example, SQL code of query:
SELECT
WL.ExtractString('A|B|C',1,'|'),
WL.ExtractString('A|B|C',1,'|', WL.FromEnd)
FROM
DUAL
Related Examples:
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Unit examples (WINDEV): Overloading WLanguage functions
[ + ] Overloading WLanguage functions. This example overloads the Trace function and it is used to: - Display a "normal" trace - Display a trace and save the data in a file - Perform a file trace (the information is saved in a file)
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