Question

我想检查列col中是否存在该号码并运行mysqli_num_rows。到目前为止，它使用以下代码：

//$conn = connection to mysql.

$row1sql = "SELECT * from chktable where col='1'";
$row2sql = "SELECT * from chktable where col='2'";
$row3sql = "SELECT * from chktable where col='3'";
$row4sql = "SELECT * from chktable where col='4'";

$query1sql = $conn->query($row1sql);
$query2sql = $conn->query($row2sql);
$query3sql = $conn->query($row3sql);
$query4sql = $conn->query($row4sql);

$num1 = mysqli_num_rows($query1sql);    
$num2 = mysqli_num_rows($query2sql);    
$num3 = mysqli_num_rows($query3sql);    
$num4 = mysqli_num_rows($query4sql);

我根据$num编辑其他代码。

如何缩短此代码？我可以使用for声明吗？如果适用，我该如何使用它？或者其他任何缩短此代码的方法？

感谢。

Answer 1

这将获得col值和行数，仅用于col值1,2,3,4

$query = $conn->query("SELECT col, count(*) as num FROM chktable GROUP BY col WHERE col IN (1,2,3,4);");
while($row = $query->fetch_object())
    echo "Col: ".$row->col.", Num:".$row->num;

你可以在while循环中做任何你想做的检查

没有准备好的声明缩短代码

1 个答案: