php 如何两次通过mysql结果？
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How to go through mysql result twice?
提问by A-OK
For whatever reason I need to go through a mysql result set twice. Is there a way to do it? I don't want to run the query twice and I don't want to have to rewrite the script so that it stores the rows somewhere and then reuses them later.
无论出于何种原因，我都需要两次通过 mysql 结果集。有没有办法做到这一点？我不想运行查询两次，也不想重写脚本以便它将行存储在某处，然后在以后重用它们。
回答by Shef
This is how you can do it:
你可以这样做：
$result = mysql_query(/* Your query */);
while($row = mysql_fetch_assoc($result)){
// do whatever here...
}
// set the pointer back to the beginning
mysql_data_seek($result, 0);
while($row = mysql_fetch_assoc($result)){
// do whatever here...
}
However, I would have to say, this doesn't seem the right way to handle this. Why not do the processing within the first loop?
但是，我不得不说，这似乎不是处理此问题的正确方法。为什么不在第一个循环内进行处理？
回答by phant0m
Try whether mysql_data_seek()does what you need.
尝试mysql_data_seek()是否满足您的需求。
mysql_data_seek() moves the internal row pointer of the MySQL result associated with the specified result identifier to point to the specified row number. The next call to a MySQL fetch function, such as mysql_fetch_assoc(), would return that row.
row_number starts at 0. The row_number should be a value in the range from 0 to mysql_num_rows() - 1. However if the result set is empty (mysql_num_rows() == 0), a seek to 0 will fail with a E_WARNING and mysql_data_seek() will return FALSE
mysql_data_seek() 将与指定结果标识符关联的 MySQL 结果的内部行指针移动到指定的行号。对 MySQL fetch 函数的下一次调用，例如 mysql_fetch_assoc()，将返回该行。
row_number 从 0 开始。 row_number 应该是从 0 到 mysql_num_rows() - 1 范围内的值。但是，如果结果集为空 (mysql_num_rows() == 0)，则对 0 的查找将失败并显示 E_WARNING 和 mysql_data_seek () 将返回 FALSE
回答by guitarlass
回答by Clintonio
Alternative to the data seek is to store the values into an array:
数据查找的替代方法是将值存储到数组中：
$arrayVals = array();
$result = mysql_query(/* Your query */);
while($row = mysql_fetch_assoc($result)){
$arrayVals[] = $row;
}
// Now loop over the array twice instead
$len = count($arrayVals);
for($x = 0; $x < $len; $x++) {
$row = $arrayVals[$x];
// Do something here
}
$len = count($arrayVals);
for($x = 0; $x < $len; $x++) {
$row = $arrayVals[$x];
// Do something else here
}
回答by BugFinder
I confess I haven't tried this, but have you tried after your first iteration
我承认我没有尝试过这个，但是你在第一次迭代后尝试过吗
mysql_data_seek($queryresult,0);
to go to the first record?
去第一条记录？
回答by Steve
You can use mysql_data_seekto move the internal pointer to the beginning of the data set. Then, you can just iterate through it again.
您可以使用mysql_data_seek将内部指针移动到数据集的开头。然后，您可以再次遍历它。
回答by Andreas Eriksson
Well, you could always count the number of rows you read, and then do something like this:
好吧，你总是可以计算你阅读的行数，然后做这样的事情：
if (rownumber == mysql_num_rows($result)) { mysql_data_seek($result, 0); }
Don't know why you would need to, but there it is.
不知道你为什么需要，但它就在那里。
