Think/Db/Driver.php
protected function parseTable($tables)
    {
        // 支持别名定义
        if (is_array($tables)) {
            $array = [];
            foreach ($tables as $table => $alias) {
                if (!is_numeric($table)) {
                    $array[] = $this->parseKey($table).' '.$this->parseKey($alias);
                } else {
                    $array[] = $this->parseKey($alias);
                }
            }
            $tables = $array;
        } elseif (is_string($tables)) {
            $tables = explode(',', $tables);
            array_walk($tables, [&$this, 'parseKey']);
        }

        return implode(',', $tables);
    }
protected function parseTable($tables)
    {
        // 支持别名定义
        if (is_array($tables)) {
            $array = [];
            foreach ($tables as $table => $alias) {
                if (!is_numeric($table)) {
                    $array[] = $this->parseKey($table).' '.$this->parseKey($alias);
                } else {
                    $array[] = $this->parseKey($alias);
                }
            }
            $tables = $array;
        } elseif (is_string($tables)) {
            $tables = explode(',', $tables);
            array_walk($tables, [&$this, 'parseKey']);
        }

        return implode(',', $tables);
    }
table分析


@param string|array $tables

@return string