sql語句不適合我

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我正在開發一個php項目，客戶可以喜歡並且不像某個帖子。在MySQL數據庫喜歡clomn應增加或減少1即（+1或-1）下面是我的SQL語法我不知道哪裏出錯請幫忙。sql語句不適合我

$time = date("Y-m-d H:i:s"); 
$sql_likes2 = "UPDATE `tble_likes` SET likes = `tble_likes`.`likes`-1 WHERE `tble_likes`.`postaID` = ? AND `tble_likes`.`useremail` = ?"; 
$SQL_statement_likes= $this->conn->prepare($sql_likes2); 
$SQL_statement_likes->bindParam(1,$this->posta2); 
$SQL_statement_likes->bindParam(2,$this->user_mail); 
$SQL_statement_likes->execute(); 
if($SQL_statement_likes==true){ 
    echo $this->user_mail; 
    $sql_countL = "SELECT COUNT(likes) AS SUM FROM tble_likes WHERE postaID=? GROUP BY postaID LIMIT 1"; 
    $sql_statement_countL = $this->conn->prepare($sql_countL); 
    $sql_statement_countL->bindParam(1,$this->posta); 
    $sql_statement_countL->execute(); 
    if($sql_statement_countL==true){ 
     $row=$sql_statement_countL->fetch(); 
     $unlike = $row[0]; 
     echo $unlike; 
    } 
}

來源

2017-06-02 Seyyid Said

列的數量不會增加或列的值減去後改變。取而代之的是使用簡單的select ... like查詢。 – Shadow

嘗試'SUM'而不是'COUNT'。 Count是單獨的行，sum是這些行的累積值。 – aynber

我甚至不清楚你是如何在首位存儲的。 – Shadow

SUM是一個保留字，所以

$sql_countL = "SELECT COUNT(likes) AS sumRows FROM tble_likes WHERE postaID=? GROUP BY postaID LIMIT 1";

來源

2017-06-02 21:11:07

sql語句不適合我

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