Php 从数据库中操作字符串
我有一个表,其中包含字段Php 从数据库中操作字符串,php,sql-server,string,Php,Sql Server,String,我有一个表,其中包含字段studentId和AttendaceStatus AttendanceStatus是一个varchar(2)类型字符串。它的值类似于“ppppaappp” 如何计算“p”和“A”的数量并在PHP文件中显示?您可以实现一个简单的循环,对给定字符串中出现的字符进行计数: <?php $input = 'PPPPAAAPPP'; $counts = []; foreach (str_split($input) as $char) { if (isset($cou
studentId
和AttendaceStatus
AttendanceStatus
是一个varchar(2)
类型字符串。它的值类似于“ppppaappp”
如何计算“p”和“A”的数量并在PHP文件中显示?您可以实现一个简单的循环,对给定字符串中出现的字符进行计数:
<?php
$input = 'PPPPAAAPPP';
$counts = [];
foreach (str_split($input) as $char) {
if (isset($counts[$char])) {
$counts[$char]++;
} else {
$counts[$char] = 1;
}
}
print_r($counts);
您可以直接使用sql查询:
SELECT SUM(CASE WHEN AttendaceStatus = 'P' THEN 1 ELSE 0 END ) AS present, SUM( CASE WHEN AttendaceStatus = 'A' THEN 1 ELSE 0 END ) AS absent
FROM tablename
如何将字段设置为
VARHCAR(2)
并保存“ppppaappp”的值?它将给出错误。
SELECT SUM(CASE WHEN AttendaceStatus = 'P' THEN 1 ELSE 0 END ) AS present, SUM( CASE WHEN AttendaceStatus = 'A' THEN 1 ELSE 0 END ) AS absent
FROM tablename