我有一个 MySQL 数据库(版本 5.2 CE),我有一个表,我想根据用户给出的 WHERE 条件(来自数组列表)将其过滤到另一个表中。我想针对用户选择的拆分对这个新表执行计数查询。例如,来自 TableName WHERE 的 COUNT(*) [userConditions like gender=male and gender=female, etc]。用户可以提供多个 WHERE 条件,但 COUNT 查询一次只能采用一个条件。因此,我将我的方法(执行此查询)设为一个数组,以根据用户选择的条件数量返回多个查询,然后在 for 循环中执行每个查询。但是,这似乎以两种方式给了我编译错误:i)我在 String[] 方法中返回构建字符串的方式和 ii)我执行 COUNT 查询的方式。这些问题的代码:
private String countQuery;
public SetupSubsamplePopulation(UserSelectedSplit split) {
this.split = split;
// connect to the database
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql?zeroDateTimeBehavior=convertToNull","root", "sharadha_1992");
String buildSelectQuery = buildSelectQueryForCode();
String getRowsFromTable = getNumberOfRows();
stmt = connection.createStatement();
rows = stmt.executeUpdate(buildSelectQuery);
ResultSet rs = stmt.executeQuery(getRowsFromTable);
for (int i=0; i<getCountOfWhereCondition().length; i++){
//where I get the executeQuery error
ResultSet rs1= stmt.execute(getCountOfWhereCondition());
while (rs1.next()){
rowsCount= rs.getRow();
rows_count++;
}
}
while (rs.next()) {
rows = rs.getRow();
rows_inserted++;
}
System.out.println(rows_inserted);
System.out.println(rows_count);
} catch (Exception e) {
e.printStackTrace();
}
}
返回 COUNT 个查询数组的方法:
public String[] getCountOfWhereCondition() {
countQuery="SELECT COUNT (*) FROM (SELECT * from mygrist_samples.subsample_population WHERE ";
for (int i = 0; i < split.getSplitConditions().size(); i++) {
String getCorrespondingCodeFromDatabase = split.getSplitConditions().get(i).getCode();
getCorrespondingCodeFromDatabase = getCorrespondingCodeFromDatabase.replaceAll("-", "_");
Enumerations enum1 = new Enumerations();
String getCorrespondingRelationshipOperator = enum1.getOperator(split.getSplitConditions().get(i).getRelationship());
countQuery+=getCorrespondingCodeFromDatabase + " " + getCorrespondingRelationshipOperator + " '" + split.getSplitConditions().get(i).getAnswer() + "'";
}
countQuery+=")";
System.out.println(countQuery);
//error which doesn't allow me to return a string
return countQuery;
}
有人可以告诉我如何明智地实施吗?非常感谢你。