<?php
function I($name, $default = '', $filter = null, $datas = null)
{
    return input($name, $default, $filter);
}

<?php
$info = M('user_follow')->where(wp_where($map))->find();

<?php
function wp_where($field)
{
    if (!is_array($field)) {
        return $field;
    }

    $res = [];
    foreach ($field as $key => $value) {
        if (is_numeric($key) || (is_array($value) && count($value) == 3)) {
            if (strtolower($value[1]) == 'exp' && !is_object($value[2])) {
                $value[2] = Db::raw($value[2]);
            }
            $res[] = $value;
        } elseif (is_array($value)) {
            if (strtolower($value[0]) == 'exp' && !is_object($value[1])) {
                $value[1] = Db::raw($value[1]);
            }
            $res[] = [
                $key,
                $value[0],
                $value[1]
            ];
        } else {
            $res[] = [
                $key,
                '=',
                $value
            ];
        }
    }
    //    dump($res);
    return $res;
}

<?php
public static function __callStatic($method, $args)
{
    return call_user_func_array([static::connect(), $method], $args);
}

<?php
public static function connect($config = [], $name = false, $query = '')
{
    // 解析配置参数
    $options = self::parseConfig($config ?: self::$config);

    $query = $query ?: $options['query'];

    // 创建数据库连接对象实例
    self::$connection = Connection::instance($options, $name);

    return new $query(self::$connection);
}

<?php
//\think\db\Query::raw
public function raw($value)
{
    return new Expression($value);
}

<?php
public function where($field, $op = null, $condition = null)
{
    $param = func_get_args();
    array_shift($param);
    return $this->parseWhereExp('AND', $field, $op, $condition, $param);
}

<?php
protected function parseWhereExp($logic, $field, $op, $condition, array $param = [], $strict = false)
{
    ...省略
    if ($field instanceof Expression) {
        return $this->whereRaw($field, is_array($op) ? $op : [], $logic);
    } elseif ($strict) {
        // 使用严格模式查询
        $where = [$field, $op, $condition, $logic];
    } elseif (is_array($field)) {
        // 解析数组批量查询
        return $this->parseArrayWhereItems($field, $logic);
    }
    ...省略
    return $this;
}

<?php
protected function parseArrayWhereItems($field, $logic)
{
    if (key($field) !== 0) {
        $where = [];
        foreach ($field as $key => $val) {
            if ($val instanceof Expression) {
                $where[] = [$key, 'exp', $val];
            } elseif (is_null($val)) {
                $where[] = [$key, 'NULL', ''];
            } else {
                $where[] = [$key, is_array($val) ? 'IN' : '=', $val];
            }
        }
    }
    else {
        // 数组批量查询
        $where = $field;
    }

    if (!empty($where)) {
        $this->options['where'][$logic] = isset($this->options['where'][$logic]) ? array_merge($this->options['where'][$logic], $where) : $where;
    }

    return $this;
}

<?php
public function find($data = null)
{
    if ($data instanceof Query) {
        return $data->find();
    } elseif ($data instanceof \Closure) {
        $data($this);
        $data = null;
    }

    $this->parseOptions();

    if (!is_null($data)) {
        // AR模式分析主键条件
        $this->parsePkWhere($data);
    }

    $this->options['data'] = $data;

    $result = $this->connection->find($this);

    if ($this->options['fetch_sql']) {
        return $result;
    }

    // 数据处理
    if (empty($result)) {
        return $this->resultToEmpty();
    }

    if (!empty($this->model)) {
        // 返回模型对象
        $this->resultToModel($result, $this->options);
    } else {
        $this->result($result);
    }

    return $result;
}

<?php
public function find(Query $query)
{
    // 分析查询表达式
    $options = $query->getOptions();
    $pk      = $query->getPk($options);

    $data = $options['data'];
    $query->setOption('limit', 1);
    ...

    $query->setOption('data', $data);

    // 生成查询SQL
    $sql = $this->builder->select($query);

    $query->removeOption('limit');

    $bind = $query->getBind();

    if (!empty($options['fetch_sql'])) {
        // 获取实际执行的SQL语句
        return $this->getRealSql($sql, $bind);
    }

    // 事件回调
    $result = $query->trigger('before_find');

    if (!$result) {
        // 执行查询
        $resultSet = $this->query($sql, $bind, $options['master'], $options['fetch_pdo']);

        if ($resultSet instanceof \PDOStatement) {
            // 返回PDOStatement对象
            return $resultSet;
        }

        $result = isset($resultSet[0]) ? $resultSet[0] : null;
    }
    ...

        return $result;
}