>Can anyone show me the proper way to embed an SQL statement - specifically the SELECT statement - into an event (in my case the click event of a command button)
>
>Actually, I wanted to retrieve a login_id from my table, called tbl_staff, if the input login_id supplied by the user, in this case the login_id entered into a text box called cLoginID, exists in the table.
>
>I tried
>
>(line 1) =SELECT login_id;
>(line 2) FROM tbl_staff;
>(line 3) INTO cString2;
>(line 4) WHERE login_id = ThisForm.cLoginID.value
>
>At Line 3, i wanted to store the return value into a variable so that i can check the variable to see whether it's a valid login_id based on whether the SELECT statement was successful or not
>
>When i run this particular form of mine and pressed the command button after entering a value into the text box, the program run stopped and gave me a message
>
> SELECT variable not found
>
>So...can anyone show me where i went wrong?

See Paul's reply, he's got a good suggestion.
I just want to add the reason why your SELECT don't work: the result of a SELECT must be put in a table, cursor or array. It cannot be a character variable.
Here's the correct SELECT statement for your question:

SELECT login_id;
FROM tbl_staff;
INTO CURSOR Temp;
WHERE login_id = ThisForm.cLoginID.value

cString2 = Temp.Login_ID
USE