如何在mysql查询中写一个字符串变量？

Question

我想实现此查询：

if(x=1){
$update = "close = '$date'";
}
else {
$update = "open = '$date'";
}
$query = "Update table1 set $update where id=100";
mysql_query($query);

但我收到错误，Mysql无法执行查询？

Answer 1

   <?php
    if($x==1){
    $update = "close = '".$date."'";
    }
    else {
    $update = "open = '".$date."'";
    }
    $query = "update table1 set $update where id=100";
    mysql_query($query);
    ?>

Answer 2

将您的查询放在引号中。请尝试以下方法：

if(x==1){
  $update = "close='".$date."'";
}
else {
  $update = "open = '".$date."'";
}
$query = "Update table1 set ".$update." where id=100";
mysql_query($query) or die(mysql_error());

使用mysql_error（）来检查你从mysql获得的错误

Answer 3

使用此

<?php


if(x==1){
$update = "close = '$date'";
}
else {
$update = "open = '$date'";
}
$query = "Update table1 set '".$update."' where id=100";
mysql_query($query);

?>

Answer 4

尝试使用此代码........

<?php
if($x==1){ // use $ for variables
    $update = "close = '".$date."' "; //always concatenate variables
}
else {
    $update = "open = '".$date."' ";
}
$query = "Update table1 set '".$update."' where id=100";
mysql_query($query, $connection); // don`t forget to add mysql connection 

?>

Answer 5

Replace 
$query = Update table1 set $update where id=100;

to
$query = "Update table1 set ".$update." where id=100";