Another way to create a new variable is to drag and drop a single SQL element from the SQL Elements panel to the empty space at the bottom of the Variables panel, or to drag and drop one or more column values displayed by clicking the Values button. In the case of column values, a variable containing a single SQL Numeric Literal, String Literal or Date Literal is created as appropriate for each column value. This technique saves having to edit the properties of a numeric, string or date literal to set the desired value.
As with creating variables from selected columns, use of the right arrow selection button or double-clicking the desired SQL element or column value provides an alternative to dragging and dropping an element or value.
When a SQL element is placed on top of another element on the Variables panel, whether by dragging and dropping it, selecting it with the right arrow or by double-clicking it, the new element will either replace the target element if the new element cannot take operands, or will be inserted into the expression tree at that point, with the replaced element moved to an empty operand of the new SQL element.