获得结果集的行数

Question

请帮助!!!!!!! 在数据库我有2行与此查询。

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SELECT D.DEALER_CODE 
FROM SCOTT.T_DEALERSHIP D,SCOTT.T_DEALER_BILLING DB 
WHERE D.DEALER_CODE = DB.DEALER_CODE 
    AND DEALER_NAME LIKE 'XTIME%' 
    AND (RNR_CUST_NUM = '546' OR RNR_CUST_NUM = '43356'OR RNR_CUST_NUM = '7637055' OR RNR_CUST_NUM ='7637055' OR RNR_CUST_NUM IS NULL) 
    AND (RCI_STORE_NUMBER IS NULL OR RCI_STORE_NUMBER = '05') 
    AND (RCI_AREA_NUMBER = '01'OR RCI_AREA_NUMBER IS NULL) 
    AND (RCI_DEALER_NUMBER IS NULL AND DEALER_Address1 LIKE UPPER('1500 ORACLE%')         
    AND DEALER_CITY =UPPER('BAKERSFIELD') AND DEALER_ZIP LIKE'6%') 

下面的代码，我只得到1行的时候有2条记录在数据库中。当数据库中只有一条记录时，只有一条记录有效，但当有更多记录时不起作用。另外rs.last()方法被跳过并退出结果集。我必须评论它执行一条记录。我不想使用COUNT。

ResultSet rs = stmt.executeQuery(sql1); 
System.out.println("" + sql1); 

while(rs.next()) { 
    rs.last(); 
    int Rows = rs.getRow(); 
    System.out.println("Rows are " + Rows); 
} 

Answer 1

如果你想要做的就是在统计数据库中的记录，那么你真的应该使用形式SELECT count(*) FROM ...的查询。如果你真的需要执行查询你上面列出的方式，那么你想设置一个计数器变量您while循环之外，像这样：

int rowNum = 0; 
while (rs.next()) { 
    rowNum++; 
} 
System.out.println("Number of records: "+rowNum); 

Answer 2

我强烈反对通过JDBC返回所有的数据到Java刚确定行数。如果你只是想知道有多少行符合条件，然后做一个SELECT COUNT（*）查询：

在SQL：

SELECT COUNT(*) 
FROM SCOTT.T_DEALERSHIP D,SCOTT.T_DEALER_BILLING DB 
WHERE D.DEALER_CODE = DB.DEALER_CODE 
    AND DEALER_NAME LIKE 'XTIME%' 
    AND (RNR_CUST_NUM = '546' OR RNR_CUST_NUM = '43356'OR RNR_CUST_NUM = '7637055' OR RNR_CUST_NUM ='7637055' OR RNR_CUST_NUM IS NULL) 
    AND (RCI_STORE_NUMBER IS NULL OR RCI_STORE_NUMBER = '05') 
    AND (RCI_AREA_NUMBER = '01'OR RCI_AREA_NUMBER IS NULL) 
    AND (RCI_DEALER_NUMBER IS NULL AND DEALER_Address1 LIKE UPPER('1500 ORACLE%') 
    AND DEALER_CITY =UPPER('BAKERSFIELD') AND DEALER_ZIP LIKE'6%') 

然后在Java中：

ResultSet rs = stmt.executeQuery(sql1); 
System.out.println("" + sql1); 

int rows = 0; 
if(rs.next()) { 
    rows = rs.getInt(); 
} 
System.out.println("Rows are " + rows); 

编辑基于OP的评论

要从数据库除了计数以外的值，只需扫描值。

SQL：

SELECT D.DEALER_CODE 
FROM SCOTT.T_DEALERSHIP D,SCOTT.T_DEALER_BILLING DB 
WHERE D.DEALER_CODE = DB.DEALER_CODE 
    AND DEALER_NAME LIKE 'XTIME%' 
    AND (RNR_CUST_NUM = '546' OR RNR_CUST_NUM = '43356'OR RNR_CUST_NUM = '7637055' OR RNR_CUST_NUM ='7637055' OR RNR_CUST_NUM IS NULL) 
    AND (RCI_STORE_NUMBER IS NULL OR RCI_STORE_NUMBER = '05') 
    AND (RCI_AREA_NUMBER = '01'OR RCI_AREA_NUMBER IS NULL) 
    AND (RCI_DEALER_NUMBER IS NULL AND DEALER_Address1 LIKE UPPER('1500 ORACLE%') 
    AND DEALER_CITY =UPPER('BAKERSFIELD') AND DEALER_ZIP LIKE'6%') 

的Java：

ResultSet rs = stmt.executeQuery(sql1); 
System.out.println("" + sql1); 

List<String> rows = new ArrayList<String>(); 
while(rs.next()) { 
    rows.add(rs.getString()); 
} 
System.out.println("There are " + rows.size() + " rows.");