在我的科目表中，按学期和月份分列所有学生的课程，每个月分数
[
{
"id": "4", - this is the subject id
"userid": "1",
"name": "bio",
"semester": "3", - semester
"month": "5", - the month
"points": "652" - points of this class
"time": "2017-06-18 22:45:04"
},
{
"id": "3", - this is the subject id
"userid": "1",
"name": "math",
"semester": "3", - semester
"month": "4", - the month
"points": "33" - points of this class
"time": "2017-05-15 22:45:04"
},
{
"id": "2", - this is the subject id
"userid": "1",
"name": "chem",
"semester": "1", - semester
"month": "3", - the month
"points": "22" - points of this class
"time": "2017-04-11 22:45:04"
},
{
"id": "1", - this is the subject id
"userid": "1",
"name": "phy",
"semester": "1", - semester
"month": "2", - the month
"points": "10" - points of this class
"time": "2017-02-10 22:45:04"
}
]
这是我试过的
$sql = "SELECT users.id userid,users.name username,subjects.id subjectsid, subjects.name subjectname, subjects.points activepts FROM tbusers AS users INNER JOIN tbsubjects AS subjects ON users.id = subjects.userid WHERE users.id = '$userid' ORDER BY subjects.time DESC";
try {
$db = new db();
$db = $db->connect();
$stmt = $db->prepare($sql);
$stmt->execute();
$user = $stmt->fetchAll(PDO::FETCH_OBJ);
$db = null;
if(empty($user)) {
$response->getBody()->write
('
{
"error":
{
"message":"Invalid"
}
}');
} else {
$response->getBody()->write(json_encode($user));
}
} catch(PDOException $e) {}
我从查询得到的当前输出是每个因为fetchAll的多个响应我可以将其更改为fetch但是它不会获得其他数据
[
{
"userid": "1",
"username": "joe",
"subjectid": "4",
"subjectname": "bio",
"activepts": "652"
},
"userid": "1",
"username": "joe",
"subjectid": "3",
"subjectname": "math",
"activepts": "33"
},
"userid": "1",
"username": "joe",
"subjectid": "2",
"subjectname": "chem",
"activepts": "22"
},
"userid": "1",
"username": "joe",
"subjectid": "1",
"subjectname": "phy",
"activepts": "10"
}
]
我的问题是如何将它们合并到一个响应中并在预期的输出中返回以下数据（我已经添加了每个字段的一些描述来解释它）
预期输出
[
{
"userid": "1", - from users table
"username": "joe", - from users table
"subjectsid": "1", - first subject id for the student in this case the one for phy
"subjectname": "bio", - current subject name
"activepts": "652", - points of current month
"totalpts": "717", - total points of all subjects for this student
"sem1": "32", - total points of all subjects for this student of semester 1
"sem2": "0", - total points of all subjects for this student of semester 2
"sem3": "685", - total points of all subjects for this student of semester 3
}
]
答案 0 :(得分：2)
问题是，你想要获取科目，而不是学生。所以，我颠倒了FROM和LEFT JOIN。因此，当您想要一个主题列表时，您将从SELECT ... FROM主题开始。然后，如果您需要每个主题的其他详细信息（如用户名等），则应用LEFT JOIN，这意味着：将所有需要的详细信息（用户名等）加入到LEFT表的每个记录中，例如：主表（在你的情况下是表＆＃34;科目＆＃34;）。
祝你好运！<?php
try {
$dbAdapter = new DbAdapter();
$connection = $dbAdapter->connect();
/*
* I renamed user id variable (from $userId to $userid1) in order to show you that you can
* provide more users if you wish. Then you just have to extend
* the WHERE clause in the sql statement and the bindings array.
*/
$userid1 = 1;
/*
* The sql statement - it will be prepared.
*
* ======================================================
* I'm not sure about the following fields - because you
* didn't provide proper selection criteria for them:
*
* 1) "subjectsid": "1", - first subject id for the student in this case the one for phy
* 2) "subjectname": "bio", - current subject name
* ======================================================
*/
$sql = 'SELECT
subjects.userid,
users.name AS username,
(
SELECT id
FROM tbsubjects
WHERE userid = subjects.userid
ORDER BY id ASC
LIMIT 1
) AS subjectsid,
(
SELECT name
FROM tbsubjects
WHERE
userid = subjects.userid
ORDER BY time DESC
LIMIT 1
) AS subjectname,
(
SELECT IFNULL(SUM(points), 0)
FROM tbsubjects
WHERE
userid = subjects.userid
AND month = DATE_FORMAT(NOW(), "%c")
) AS activepts,
IFNULL(SUM(subjects.points), 0) AS totalpts,
(
SELECT IFNULL(SUM(points), 0)
FROM tbsubjects
WHERE
userid = subjects.userid
AND semester = 1
) AS sem1,
(
SELECT IFNULL(SUM(points), 0)
FROM tbsubjects
WHERE
userid = subjects.userid
AND semester = 2
) AS sem2,
(
SELECT IFNULL(SUM(points), 0)
FROM tbsubjects
WHERE
userid = subjects.userid
AND semester = 3
) AS sem3
FROM
tbsubjects AS subjects
LEFT JOIN tbusers AS users ON users.id = subjects.userid
WHERE subjects.userid = :userid1
GROUP BY subjects.userid
ORDER BY subjects.time DESC';
/*
* The input parameters list for the prepared sql statement.
*/
$bindings = array(
':userid1' => $userid1,
);
/*
* Prepare and validate the sql statement.
*
* --------------------------------------------------------------------------------
* If the database server cannot successfully prepare the statement, PDO::prepare()
* returns FALSE or emits PDOException (depending on error handling settings).
* --------------------------------------------------------------------------------
*/
$statement = $connection->prepare($sql);
if (!$statement) {
throw new UnexpectedValueException('The sql statement could not be prepared!');
}
/*
* Bind the input parameters to the prepared statement.
*
* -----------------------------------------------------------------------------------
* Unlike PDOStatement::bindValue(), when using PDOStatement::bindParam() the variable
* is bound as a reference and will only be evaluated at the time that
* PDOStatement::execute() is called.
* -----------------------------------------------------------------------------------
*/
foreach ($bindings as $key => $value) {
$bound = $statement->bindValue(
getInputParameterName($key)
, $value
, getInputParameterDataType($value)
);
if (!$bound) {
throw new UnexpectedValueException('An input parameter can not be bound!');
}
}
/*
* Execute the prepared statement.
*
* ------------------------------------------------------------------
* PDOStatement::execute returns TRUE on success or FALSE on failure.
* ------------------------------------------------------------------
*/
$executed = $statement->execute();
if (!$executed) {
throw new UnexpectedValueException('The prepared statement could not be executed!');
}
/*
* Fetch users list - array of objects.
*/
$users = $statement->fetchAll(PDO::FETCH_OBJ);
if ($users === FALSE) {
throw new UnexpectedValueException('Fetching users list failed!');
}
/*
* Close connection.
*/
$connection = NULL;
/*
* Handle results.
*/
if (empty($users)) {
$response->getBody()->write(
'{
"error": {
"message":"Invalid"
}
}'
);
} else {
$response->getBody()->write(json_encode($users));
}
} catch (PDOException $exc) {
echo $exc->getMessage();
// $logger->log($exc);
exit();
} catch (Exception $exc) {
echo $exc->getMessage();
// $logger->log($exc);
exit();
}
/**
* Get the name of an input parameter by its key in the bindings array.
*
* @param int|string $key The key of the input parameter in the bindings array.
* @return int|string The name of the input parameter.
*/
function getInputParameterName($key) {
return is_int($key) ? ($key + 1) : (':' . ltrim($key, ':'));
}
/**
* Get the PDO::PARAM_* constant, e.g the data type of an input parameter, by its value.
*
* @param mixed $value Value of the input parameter.
* @return int The PDO::PARAM_* constant.
*/
function getInputParameterDataType($value) {
$dataType = PDO::PARAM_STR;
if (is_int($value)) {
$dataType = PDO::PARAM_INT;
} elseif (is_bool($value)) {
$dataType = PDO::PARAM_BOOL;
}
return $dataType;
}
对于我的项目，我开发了一个DbAdapter类。方法名称不言自明。所以，每个网页内不再有spagetti代码:-)但是只是：
您问题的解决方案如下：
<?php
//***********************************************************************************
// Put this in a php file (like db.php) to include whereever you need db data access.
//***********************************************************************************
//
// Db configs.
define('DB_HOST', '...');
define('DB_PORT', 3306);
define('DB_DBNAME', '...');
define('DB_CHARSET', 'utf8');
define('DB_USERNAME', '...');
define('DB_PASSWORD', '...');
define('DB_DRIVER_NAME', 'mysql');
// Create db adapter.
$dbAdapter = new DbAdapter(DB_HOST, DB_DBNAME, DB_USERNAME, DB_PASSWORD, DB_PORT, DB_CHARSET);
//***********************************************************************************
$userid1 = 1;
// Sql statement.
$sql = 'SELECT ... FROM ... WHERE subjects.userid = :userid1 GROUP BY ... ORDER BY ...';
// Input parameters.
$bindings = array(
':userid1' => $userid1,
);
// Fetch users.
$users = $dbAdapter->fetchAll($sql, $bindings);
// Disconnect from db.
$dbAdapter->disconnect();
/*
* Handle results.
*/
if (empty($users)) {
//...
} else {
//...
}
要调用的适配器方法是public个：
全部： - ）
<?php
/*
* Database adapter.
*/
/**
* Database adapter.
*/
class DbAdapter {
/**
* Connection configs.
*
* @var array
*/
private $connectionConfigs;
/**
* Database connection.
*
* @var PDO
*/
private $connection;
/**
* PDO statement.
*
* @var PDOStatement
*/
private $statement;
/**
*
* @param string $host [optional] Host.
* @param string $dbname [optional] Database name.
* @param string $username [optional] User name.
* @param string $password [optional] Password.
* @param string $port [optional] Port.
* @param string $charset [optional] Character set.
* @param string $driverName [optional] Driver name.
* @param array $driverOptions [optional] Driver options.
* @return string DSN string.
*/
public function __construct($host = '', $dbname = ''
, $username = '', $password = '', $port = 3306, $charset = 'utf8', $driverName = 'mysql'
, $driverOptions = array(
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_EMULATE_PREPARES => FALSE,
PDO::ATTR_PERSISTENT => TRUE,
)) {
$this->setConnectionConfigs(array(
'host' => $host,
'dbname' => $dbname,
'username' => $username,
'password' => $password,
'port' => $port,
'charset' => $charset,
'driverName' => $driverName,
'driverOptions' => $driverOptions,
));
}
/**
* Connect to db, e.g. create a PDO instance.
*
* @return $this
* @throws PDOException
*/
public function connect() {
if (!isset($this->connection) || !$this->connection) {
try {
$this->connection = new PDO(
$this->createDsn(
$this->connectionConfigs['host']
, $this->connectionConfigs['dbname']
, $this->connectionConfigs['port']
, $this->connectionConfigs['charset']
, $this->connectionConfigs['driverName']
)
, $this->connectionConfigs['username']
, $this->connectionConfigs['password']
, $this->connectionConfigs['driverOptions']
);
} catch (PDOException $pdoException) {
echo $pdoException->getMessage();
exit();
}
}
return $this;
}
/**
* Disconnect from db.
*
* @return $this
*/
public function disconnect() {
$this->connection = NULL;
return $this;
}
/**
* Create a DSN string.
*
* @param string $host Host.
* @param string $dbname Database name.
* @param string $port Port.
* @param string $charset Character set.
* @param string $driverName Driver name.
* @return string DSN string.
*/
private function createDsn($host, $dbname, $port, $charset, $driverName) {
switch ($driverName) {
default: // mysql
$dsn = sprintf('%s:host=%s;port=%s;dbname=%s;charset=%s'
, $driverName
, $host
, $port
, $dbname
, $charset
);
break;
}
return $dsn;
}
/**
* Fetch data by executing a SELECT sql statement.
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @param integer $fetchMode [optional] Fetch mode for a PDO statement.
* Must be one of the PDO::FETCH_* constants.
* @param mixed $fetchArgument [optional] Fetch argument for a PDO statement.
* @param array $fetchConstructorArguments [optional] Constructor arguments for a PDO statement
* when fetch mode is PDO::FETCH_CLASS.
* @return array An array containing the rows in the result set, or FALSE on failure.
* @throws UnexpectedValueException
*/
public function fetchAll($sql, array $bindings = array(), $fetchMode = PDO::FETCH_ASSOC, $fetchArgument = NULL, array $fetchConstructorArguments = array()) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
try {
if (isset($fetchArgument)) {
$data = $this->getStatement()->fetchAll($fetchMode, $fetchArgument, $fetchConstructorArguments);
} else {
$data = $this->getStatement()->fetchAll($fetchMode);
}
if ($data === FALSE) {
throw new UnexpectedValueException('Fetching data failed!');
}
return $data;
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
}
/**
* Fetch the next row from the result set by executing a SELECT sql statement.
* The fetch mode property determines how PDO returns the row.
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @param integer $fetchMode [optional] Fetch mode for a PDO statement.
* Must be one of the PDO::FETCH_* constants.
* @param integer $fetchCursorOrientation [optional] For a PDOStatement object representing
* a scrollable cursor, this value determines which row will be returned to the caller.
* @param integer $fetchCursorOffset [optional] The absolute number of the row in the result
* set, or the row relative to the cursor position before PDOStatement::fetch() was called.
* @return array An array containing the next row in the result set, or FALSE on failure.
* @throws Exception
*/
public function fetchOne($sql, array $bindings = array(), $fetchMode = PDO::FETCH_ASSOC, $fetchCursorOrientation = PDO::FETCH_ORI_NEXT, $fetchCursorOffset = 0) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
try {
/*
* =========================================================
* NB:
* =========================================================
* PDOStatement::fetch returns FALSE not only on failure,
* but ALSO when no record is found! This is a BUG. That's
* why I made the try-catch block: maybe on failure will
* throw an exception.
*
* Instead, PDOStatement::fetchAll returns FALSE on failure,
* but an empty array if no record is found. This is the
* correct behaviour.
* =========================================================
*/
$data = $this->getStatement()->fetch($fetchMode, $fetchCursorOrientation, $fetchCursorOffset);
return $data;
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
}
/**
* Returns a single column from the next row of a result set
* or FALSE if there are no more rows.
*
* =================================================================
* Note:
* -----
* PDOStatement::fetchColumn() should not be used to retrieve
* boolean columns, as it is impossible to distinguish a value
* of FALSE from there being no more rows to retrieve.
* Use PDOStatement::fetch() instead.
*
* Warning:
* --------
* There is no way to return another column from the same row if you
* use PDOStatement::fetchColumn() to retrieve data.
* =================================================================
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @param integer $columnNumber [optional] 0-indexed number of the
* column you wish to retrieve from the row. If no value is supplied,
* PDOStatement::fetchColumn() fetches the first column.
* @return mixed A single column from the next row of a result set
* or FALSE if there are no more rows.
* @throws Exception
*/
public function fetchColumn($sql, array $bindings = array(), $columnNumber = 0) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
try {
return $this->getStatement()->fetchColumn($columnNumber);
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
}
/**
* Store data by executing an INSERT sql statement.
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @return int Last insert id.
*/
public function insert($sql, array $bindings = array()) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
return $this->getLastInsertId();
}
/**
* Update data by executing an UPDATE sql statement.
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @return int Number of affected rows.
*/
public function update($sql, array $bindings = array()) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
return $this->getStatement()->rowCount();
}
/**
* Delete data by executing a DELETE sql statement.
*
* @param string $sql Sql statement.
* @param array $bindings [optional] Input parameters.
* @return int Number of affected rows.
*/
public function delete($sql, array $bindings = array()) {
$this
->prepareStatement($sql)
->bindInputParameters($bindings)
->executePreparedStatement()
;
return $this->getStatement()->rowCount();
}
/**
* Prepare and validate an sql statement.
*
* ----------------------------------------------------
* If the database server cannot successfully prepare
* the statement, PDO::prepare() returns FALSE or emits
* PDOException (depending on error handling settings).
* ----------------------------------------------------
*
* @param string $sql Sql statement.
* @return $this
* @throws PDOException
* @throws UnexpectedValueException
*/
private function prepareStatement($sql) {
$this->connect();
try {
$statement = $this->getConnection()->prepare($sql);
if (!$statement) {
throw new UnexpectedValueException('The sql statement can not be prepared!');
}
$this->setStatement($statement);
} catch (PDOException $pdoException) {
echo $pdoException->getMessage();
exit();
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
return $this;
}
/**
* Bind the input parameters to a prepared PDO statement.
*
* @param array $bindings Input parameters.
* @return $this
* @throws UnexpectedValueException
*/
private function bindInputParameters($bindings) {
foreach ($bindings as $key => $value) {
try {
$bound = $this->getStatement()->bindValue(
$this->getInputParameterName($key)
, $value
, $this->getInputParameterDataType($value)
);
if (!$bound) {
throw new UnexpectedValueException('A value can not be bound!');
}
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
}
return $this;
}
/**
* Get the name of an input parameter by its key in the bindings array.
*
* @param int|string $key The key of the input parameter in the bindings array.
* @return int|string The name of the input parameter.
*/
private function getInputParameterName($key) {
return is_int($key) ? ($key + 1) : (':' . ltrim($key, ':'));
}
/**
* Get the PDO::PARAM_* constant, e.g the data type of an input parameter, by its value.
*
* @param mixed $value Value of the input parameter.
* @return int The PDO::PARAM_* constant.
*/
private function getInputParameterDataType($value) {
$dataType = PDO::PARAM_STR;
if (is_int($value)) {
$dataType = PDO::PARAM_INT;
} elseif (is_bool($value)) {
$dataType = PDO::PARAM_BOOL;
}
return $dataType;
}
/**
* Execute a prepared PDO statement.
*
* @return $this
* @throws UnexpectedValueException
*/
private function executePreparedStatement() {
try {
if (!$this->getStatement()->execute()) {
throw new UnexpectedValueException('The statement can not be executed!');
}
} catch (Exception $exception) {
echo $exception->getMessage();
exit();
}
return $this;
}
/**
* Get the ID of the last inserted row or of the sequence value.
*
* @param string $sequenceObjectName [optional] Name of the sequence object
* from which the ID should be returned.
* @return string The ID of the last row, or the last value retrieved from the specified
* sequence object, or an error IM001 SQLSTATE If the PDO driver does not support this.
* @throws PDOException
*/
public function getLastInsertId($sequenceObjectName = NULL) {
$this->connect();
try {
return $this->getConnection()->lastInsertId($sequenceObjectName);
} catch (PDOException $pdoException) {
echo $pdoException->getMessage();
exit();
}
}
/**
* Get connection configs.
*
* @return array
*/
public function getConnectionConfigs() {
return $this->connectionConfigs;
}
/**
* Set connection configs.
*
* @param array $connectionConfigs Connection configs.
* @return $this
*/
public function setConnectionConfigs($connectionConfigs) {
$this->connectionConfigs = $connectionConfigs;
return $this;
}
/**
* Get database connection.
*
* @return PDO Database connection.
*/
public function getConnection() {
return $this->connection;
}
/**
* Set database connection.
*
* @param PDO $connection Database connection.
* @return $this
*/
public function setConnection(PDO $connection) {
$this->connection = $connection;
return $this;
}
/**
* Get PDO statement.
*
* @return PDOStatement
*/
public function getStatement() {
return $this->statement;
}
/**
* Set PDO statement.
*
* @param PDOStatement $statement PDO statement.
* @return $this
*/
public function setStatement(PDOStatement $statement) {
$this->statement = $statement;
return $this;
}
}