Question

我必须阅读带有type，vers和variant（从EXCEL导入）的MySql表。使用三个字符串（例如：abc，6zg，qsdf）我必须通过表扫描并查明是否存在col1 = 'abc' AND col2 = '6zg' AND col3 = 'qsdf'的表条目。结果必须是“是有这样的条目”或“否”（布尔值）。 SELECT看起来怎么样？我的代码根本不起作用！

    $result = mysqli_query($db, "SELECT *  FROM $table_name 
                        WHERE Type LIKE '%$typ%'
                        AND Version LIKE '%$version%' 
                        AND Variant LIKE '%$variant%'");

Answer 1

<强> SQL

SELECT CASE WHERE COL1='abc' AND COL2='def' AND COL3='ghi' THEN 'Yes there is such an entry' ELSE 'No' END as ColumnName from your_table

Answer 2

$result = mysqli_query($db, "
SELECT IF ( EXISTS ( SELECT  *  FROM $table_name 
                        WHERE Type    LIKE '%$typ%'
                          AND Version LIKE '%$version%' 
                          AND Variant LIKE '%$variant%'
                   )
   'YES', 'NO')
";

无论满足条件的行数是多少，都会产生1行输出。此外，如果在所有3个条件中找到第一个匹配项，它将停止。

Answer 3

以下代码有效：

$row = $mysqli->query("SELECT * FROM $table WHERE Typ LIKE '$typ' AND Vers LIKE '$vers' AND Var LIKE '$var'");
$result = $row->fetch_assoc();
if ($result == NULL) {
  echo "Not found"; }
else { 
 echo "Found!"; }

mysqli_query选择with like子句

3 个答案: