PHP MySQL查询以检查记录是否存在

Muhammad Taqi 发表于 Dev

穆罕默德·塔奇

我在表中有以下数据。

+-------------+---------------+--------------+
| activity_id | activity_name | main_unit_id |
+-------------+---------------+--------------+
|           1 | DEA           |           67 |
|           2 | DEB           |           68 |
|           3 | DEC           |           68 |
|           4 | fasdfsadf     |           74 |
+-------------+---------------+--------------+

我想添加另一个活动，但是在添加之前，我必须确保针对main_unit_id没有相同的活动名称...我编写以下查询，

$SQL_CHECK_ACTIVITY = mysql_query(
    "SELECT count(*) FROM activities " .
    "WHERE main_unit_id = '67' and activity_name = 'DEA'"
);
$RESULT_SQL_CHECK_ACTIVITY = mysql_num_rows($SQL_CHECK_ACTIVITY);
echo $RESULT_SQL_CHECK_ACTIVITY;

然后打印1，这意味着针对该项目的活动已经存在...

$SQL_CHECK_ACTIVITY = mysql_query(
    "SELECT count(*) FROM activities " .
    "WHERE main_unit_id = '78' and activity_name = 'afsdaf'"
);
$RESULT_SQL_CHECK_ACTIVITY = mysql_num_rows($SQL_CHECK_ACTIVITY);
echo $RESULT_SQL_CHECK_ACTIVITY;

然后打印1，表示该项目已经存在活动...但是在这种情况下没有记录...。

穆罕默德·塔奇

$SQL_CHECK_ACTIVITY = mysql_query("SELECT * FROM activities WHERE main_unit_id = '".$project."' and activity_name = '67' limit 1");
    if(mysql_fetch_row($SQL_CHECK_ACTIVITY)) {
        echo 'a activity against this project already exists...';
      }
      else{
}

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