## 创建core/database/query/QueryBuilder.php ``` <?php namespace core\database\query; use core\database\connection\Connection; class QueryBuilder { protected $connection; protected $grammar; public $binds; public $columns; public $distinct; public $form; public $union; public $bindings = [ 'select' => [], 'from' => [], 'join' => [], 'where' => [], 'groupBy' => [], 'having' => [], 'order' => [], 'union' => [], 'unionOrder' => [], ]; protected $operators = [ '=','<','>','<=','>=','<>','!=','<=>','like','like binary','not like','ilike','&','|','^', '<<','>>','rlike','not rlike','regexp','not regexp','~','~*','!~','!~*','similar to','not similar to', 'not ilike','~~*','!~~*' ]; public function __construct(Connection $connection, $grammar) { $this->connection = $connection; // 数据库连接 $this->grammar = $grammar; // 编译成sql的类 } public function table(string $table,$as = null) { return $this->from($table,$as); // return (clone $this)->from($table,$as); } public function from($table,$as) { $this->from = $as ? "{$table} as {$as}" : $table; return $this; } public function get($columns = ['*']) { if(! is_array($columns)) $columns = func_get_args(); $this->columns = $columns; $sql = $this->toSql(); return $this->runSql($sql); } // 运行sql public function runSql($sql) { return $this->connection->select( $sql,$this->getBinds() ); } public function where($column, $operator = null, $value = null, $joiner = 'and') { if ( is_array($column)) // 如果是 where(['id' => '2','name' => 'xxh']) 这种 foreach ($column as $col => $value) $this->where($col,'=',$value); if(! in_array($operator,$this->operators)){ // 操作符不存在 $value = $operator; $operator = '='; } $type = 'Basic'; $this->wheres[] = compact( 'type', 'column', 'operator', 'value', 'joiner' ); // 存到wheres变量 $this->binds[] = $value; return $this; } public function orWhere($column, $operator = null, $value = null) { return $this->where($column, $operator, $value ,'or'); } public function find($id,$columns = ['*'],$key = 'id') { return $this->where($key,$id)->get($columns); } public function whereLike($column, $operator = null, $value = null) { return $this->where($column, $operator, $value, 'like'); } public function toSql() // 编译成sql { return $this->grammar->compileSql($this); } public function getBinds() // 绑定 { return $this->binds; } } ``` ## 创建core/database/query/MysqlGrammar ``` <?php namespace core\database\query; class MysqlGrammar { protected $selectComponents = [ 'columns', 'from', 'joins', 'wheres', 'groups', 'havings', 'orders', 'limit', 'offset', 'lock', ]; public function compileSql(QueryBuilder $query) { $sql = []; foreach ($this->selectComponents as $component) if( isset( $query->{$component})) $sql[$component] = $this->$component($query, $query->$component); return implode($sql); } protected function columns(QueryBuilder $query,$columns) { if(! $columns) $columns = ['*']; $select = 'select '; if ($query->distinct) $select = 'select distinct '; return $select . implode(',',$columns); } protected function from(QueryBuilder $query,$form) { return ' from '.$form; } protected function joins() { } protected function wheres(QueryBuilder $queryBuilder,$wheres) { if(! $wheres) return ''; $where_arrs = []; foreach ($wheres as $index => $where){ if(! $index) $where['joiner'] = ' where'; $where_arrs[] = sprintf(' %s `%s` %s ?',$where['joiner'], $where['column'], $where['operator']); } return implode($where_arrs); } protected function groups() { } protected function havings() { } protected function orders() { } protected function limit() { } protected function offset() { } protected function lock() { } } ``` ## 编辑core\database\connection\MysqlConnection.php 添加以下代码 ``` // 调用不存在的方法 调用一个新的查询构造器 public function __call($method, $parameters) { // 返回QueryBuilder类 return $this->newBuilder()->$method(...$parameters); } // 创建新的查询器 public function newBuilder() { return new QueryBuilder($this, new MysqlGrammar()); } ````  ## 运行