<variable reference> = <expression>;
An assignment statement assigns a value to a variable by evaluating an expression.
myString = 'Thank you'; VARIABLES.x = (SELECT Column1 FROM MySchema.MyTable);
Valid variables for assignment include any in-scope variable that has been declared with a declaration statement,
or the procedure
out parameters can be accessed by their fully qualified names.
CREATE VIRTUAL PROCEDURE proc (OUT STRING x, INOUT STRING y) AS BEGIN proc.x = 'some value ' || proc.y; y = 'some new value'; END