Count（）/ sum（）的ResultSetMetadata列类型

Question

In MySQL select:

count(BIGINT) returns type=-5 (BigInteger), I expected Long

sum(SMALLINT) returns type=3 (BigDecimal), I expected Integer

Is there anything that can be done?

Answer 1

The value of -5 indicates java.sql.Types.BIGINT , which is the JDBC/SQL equivalent of a Java long , so this value is entirely expected.

As to why SUM is mapped to 3, or java.sql.DECIMAL , I'm not sure. It might just be that is what MySQL does when summing not floating-point types.