Ansi SQL类型转换

Question

是否允许像在postgres中一样在ANSI SQL中转换类型:

SELECT SUM( CAST(qnty AS int) - CAST(reserve AS int) )  AS sum
...

qnty和reserve是字符列.

Answer 1

的CAST在SQL-92的溶液中加入表达.你可以在这个草案中看到它.