这是一个SQL解释器，功能不是很全，由于本身内存数据库提供的功能限制，提供的SQL也有很多的限制：

1、select不支持按字段取值，一次查询获取所有字段

2、查询条件之间的关系只支持AND

3、UPDATE一次只更新一个字段

4、不支持函数-This is an SQL parser, function is not very wide, due to the functional limitations of itself memory database, SQL provide a lot of limit

System:

1, the select does not support field values​ ​ , a query for all the fields

2, the relationship between the query only supports AND

3, UPDATE, update a field

4, does not support function