如何使用 MySQL Workbench 创建函数？

Question

I have an MSSQL background.

I am trying to create a function in MySQL Workbench by rightclicking on 'Functions' > 'Create Function' .

I insert this text to create the function into the window but it says there are errors in sql at the last line missing 'if' .(SQL below). What am I missing?

2nd Qn. (Related)

If I create the function using the function SQL (not using the menu in MySQL Workbench), the function gets created but it doesn't appear in the 'Functions' being shown in the schema am working on. What is the recommended way to create functions in MySQL Workbench?

Thanks.

CREATE FUNCTION fnIsExcluded(ConcattedString NVARCHAR(15), InValue DECIMAL)
RETURNS BIT 

BEGIN 
    DECLARE individual VARCHAR(20) DEFAULT NULL;
    DECLARE ReturnValue BIT;

    IF (LENGTH(ConcattedString)) < 1
        THEN
            SET ReturnValue = 0;


    ELSE IF ConcattedString IS NULL
    THEN
        SET ReturnValue = 0;


    ELSE IF InValue IS NULL
    THEN

        SET ReturnValue = 0;

    ELSE
     SET ReturnValue = 1;

    END IF;

     RETURN ReturnValue;

END;

Answer 1

You didn't say what version of MySQL Workbench you are using.

1) The syntax error in the routine editor you is because in older versions the editor did not handle delimiters automatically. Hence you'd need a command to change the default delimiter, like:

delimiter $$

(at the top of the text) to change the default (semicolon) to a custom one (double dollar). The reason you have to do this is that the default delimiter is needed in the function definition and if not changed the client (here MySQL Workbench) would wrongly split your function command into individual commands. However, you can update to the latest MySQL Workbench version (6.2.3 at the time of this writing) to have this handled automatically.

2) Usually changes in the db structure cannot be picked up automatically because it would mean to load all db content at a frequent intervals, which is not feasible for any non-trivial db. Hence you have to trigger this manually, by clicking the refresh button.

However, some changes (especially additions or deletions you did yourself in MySQL Workbench) either are already tracked or will be there in future versions).