Question

我有一个包含两列的表格：

ID1 | ID2
---------
 1  | A
 3  | V
 1  | C
 4  | B
 5  | Q
 1  | S

我希望能够找出是否有任何行，例如ID1 = 5和ID2 = Q，并返回真/假值。

Answer 1

是的，当然

SELECT * FROM table where ID1='5' and ID2='Q'

PHP _{（我只是猜测这个后端）}

$query = "SELECT * FROM table where ID1='5' and ID2='Q'";
$result = mysql_query($query);
if(mysql_num_rows($result)) { return true; }
else { return false; }

Answer 2

1表示TRUE代表mysql

SELECT 1
FROM your_table
WHERE ID1 = 5 AND ID2 = 'Q'

Answer 3

例如这个？

SELECT 1
FROM TABLE
WHERE ID1 = 5 AND ID2 = 'Q'

Answer 4

为您的目的进行高效查询（比其他示例更快）：

SELECT 1 FROM table where ID1='5' and ID2='Q' LIMIT 1

PHP示例：

<?php
    $query = "SELECT 1 FROM table where ID1='5' and ID2='Q' LIMIT 1";
    echo bool(mysql_num_row(mysql_query($query)));
?>

MySQL表行包含两个值

4 个答案: