public function column($field, $key = '')
{
$result = false;
if (!empty($this->options['cache'])) {
// 判断查询缓存
$cache = $this->options['cache'];
if (empty($this->options['table'])) {
$this->options['table'] = $this->getTable();
}
$guid = is_string($cache['key']) ? $cache['key'] : md5($field . serialize($this->options));
$result = Cache::get($guid);
}
if (false === $result) {
if (isset($this->options['field'])) {
unset($this->options['field']);
}
if ($key && '*' != $field) {
$field = $key . ',' . $field;
}
$pdo = $this->field($field)->fetchPdo(true)->select();
if (is_string($pdo)) {
// 返回SQL语句
return $pdo;
}
if (1 == $pdo->columnCount()) {
$result = $pdo->fetchAll(PDO::FETCH_COLUMN);
} else {
$resultSet = $pdo->fetchAll(PDO::FETCH_ASSOC);
if ($resultSet) {
$fields = array_keys($resultSet[0]);
$count = count($fields);
$key1 = array_shift($fields);
$key2 = $fields ? array_shift($fields) : '';
$key = $key ?: $key1;
foreach ($resultSet as $val) {
if ($count > 2) {
$result[$val[$key]] = $val;
} elseif (2 == $count) {
$result[$val[$key]] = $val[$key2];
} elseif (1 == $count) {
$result[$val[$key]] = $val[$key1];
}
}
} else {
$result = [];
}
}
if (isset($cache) && isset($guid)) {
// 缓存数据
if (isset($cache['tag'])) {
Cache::tag($cache['tag'])->set($guid, $result, $cache['expire']);
} else {
Cache::set($guid, $result, $cache['expire']);
}
}
} else {
// 清空查询条件
$this->options = [];
}
return $result;
}