使用 Java JDBC 对 MySQL 进行“计数”查询的返回类型是什么？
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What is the return type of a "count" query against MySQL using Java JDBC?
提问by Beladula
String query = "SELECT COUNT(*) AS count FROM table1";
ResultSet rs = DBConnection.executeQuery(query);
The above code works fine; however:
上面的代码工作正常；然而：
long count = rs.getLong("count");
This wont work, it throws SQLException. How should I get data from the ResultSet?
这行不通，它会抛出 SQLException。我应该如何从ResultSet?
采纳答案by ZenMaster
long tmpLong = rs.getLong(1);
should work from what I can recall.
应该从我能回忆起的工作开始。
EDIT:
编辑：
of course:
当然：
rs.next();
回答by Petar Minchev
Have you called rs.next()before calling rs.getLong("count");
打电话rs.next()之前你打过电话吗rs.getLong("count");
回答by Czar Pino
rs.getLonghas 2 versions rs.getLong(java.lang.String)and rs.getLong(int). For the string version use:
rs.getLong有 2 个版本rs.getLong(java.lang.String)和rs.getLong(int). 对于字符串版本使用：
long count = rs.getLong("COUNT(*)");
Since the column name is COUNT(*)
由于列名是 COUNT(*)
Based on the query used:
基于所使用的查询：
SELECT COUNT(*) AS count FROM table1
