如何从结果集中获取计数？

Question

ResultSet rs = statement.executeQuery("SELECT COUNT(DISTINCT `id`) FROM `users`");

在 MySQL 我有答案“5”，如何从 java 的结果集中得到这个 5？整数

Answer 1

将其作为 int 列获取：

int count = -1;
if (rs.next()) {
    count = rs.getInt(1);
}

Answer 2

尝试为 COUNT(DISTINCT ID) 添加别名，然后从结果集中检索别名。如果您稍后向查询添加更多逻辑，这将更具可读性和更易于维护。

ResultSet rs = statement.executeQuery("SELECT COUNT(DISTINCT `id`) as NUM_ROWS FROM `users`");

int count = -1;
if(rs.next())
{
    count = rs.getInt("NUM_ROWS");

}

如何从结果集中获取计数？

How to get count from resultset?

java

sql

resultset