SQL查询在phpmyadmin中工作，但不在php中工作 [英] SQL query working in phpmyadmin but not in php

问题描述

我进行了查询，以仅选择每个用户的最后日期.它可以在phpmyadmin中工作，但是当我想在PHP中的mysqli_query()中执行它时，它什么也没有回报，甚至没有错误.

i have made a query to select only the last date for each user. It works in phpmyadmin but when i want to execute it in a mysqli_query() in PHP it doesnt give anything back, not even an error.

代码是:

select * from table t inner join ( select User_ID, max(Date) as MaxDate from table group by User_ID ) tm on t.User_ID = tm.User_ID and t.Date = tm.MaxDate

如果您知道为什么，请告诉我:)

If you have any idea why please let me know :)

编辑 PHP代码是:

$id = $_SESSION["ID"];  
    $SqlQuery = "SELECT * from 'tablename' t inner join ( select 'User_ID', max('Date') as 'MaxDate' from 'tablename' group by 'User_ID' ) tm on 't.User_ID' = 'tm.User_ID' and 't.Date' = 'tm.MaxDate'";
    $Result = mysqli_query($link, $SqlQuery) or die ("not possible to execute query: $sql on $link");

    if ($Result->num_rows > 0) {
     while($row = $Result->fetch_assoc()) {
         echo "<br> id: ". $row['Sick_ID']. " - UserID: ". $row['User_ID']. "- Reason " . $row['Reason'] . "<br>";
     }
} else {
     echo "0 results";
}

推荐答案

将架构所有者前缀添加到选择查询中.通常会在PHP上执行mysql查询时发生.

Add the schema owner prefix to the select query. It usually happens when executing mysql queries on PHP.

Select * from data.table_name as t1 inner join data.table_name_2 as t2 .....

更好的话:

Select data.t1.id, data.t2.name from data_table_name as t1 .....

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