Represents a SQL statement to execute against a MySQL database. This class cannot be inherited.
MySqlCommand features the following methods for executing commands at a MySQL database:
Item
Description
ExecuteReader
Executes commands that return rows.
ExecuteNonQuery
Executes commands such as SQL INSERT, DELETE, and UPDATE statements.
ExecuteScalar
Retrieves a single value (for example, an aggregate value) from a database.

You can reset the CommandText property and reuse the MySqlCommand object. However, you must close the MySqlDataReader before you can execute a new or previous command.

If a MySqlException is generated by the method executing a MySqlCommand, the MySqlConnection remains open. It is the responsibility of the programmer to close the connection.

Using the '@' symbol for paramters is now the preferred approach although the old pattern of using '?' is still supported. Please be aware though that using '@' can cause conflicts when user variables are also used. To help with this situation please see the documentation on the 'allow user variables' connection string option. The 'old syntax' connection string option has now been deprecated.

The following example creates a MySqlCommand and a MySqlConnection. The MySqlConnection is opened and set as the Connection for the MySqlCommand. The example then calls ExecuteNonQuery, and closes the connection. To accomplish this, the ExecuteNonQuery is passed a connection string and a query string that is a SQL INSERT statement. `Public Sub InsertRow(myConnectionString As String) " If the connection string is null, use a default. If myConnectionString = "" Then myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass" End If Dim myConnection As New MySqlConnection(myConnectionString) Dim myInsertQuery As String = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)" Dim myCommand As New MySqlCommand(myInsertQuery) myCommand.Connection = myConnection myConnection.Open() myCommand.ExecuteNonQuery() myCommand.Connection.Close() End Sub` `public void InsertRow(string myConnectionString) { // If the connection string is null, use a default. if(myConnectionString == "") { myConnectionString = "Database=Test;Data Source=localhost;User Id=username;Password=pass"; } MySqlConnection myConnection = new MySqlConnection(myConnectionString); string myInsertQuery = "INSERT INTO Orders (id, customerId, amount) Values(1001, 23, 30.66)"; MySqlCommand myCommand = new MySqlCommand(myInsertQuery); myCommand.Connection = myConnection; myConnection.Open(); myCommand.ExecuteNonQuery(); myCommand.Connection.Close(); }`
Initializes a new instance of the MySqlCommand class.
The following example creates a MySqlCommand and sets some of its properties.

This example shows how to use one of the overloaded versions of the MySqlCommand constructor. For other examples that might be available, see the individual overload topics.

Public Sub CreateMySqlCommand() Dim myConnection As New MySqlConnection _ ("Persist Security Info=False;database=test;server=myServer") myConnection.Open() Dim myTrans As MySqlTransaction = myConnection.BeginTransaction() Dim mySelectQuery As String = "SELECT * FROM MyTable" Dim myCommand As New MySqlCommand(mySelectQuery, myConnection, myTrans) myCommand.CommandTimeout = 20 End Sub
public void CreateMySqlCommand() { MySqlConnection myConnection = new MySqlConnection("Persist Security Info=False; database=test;server=myServer"); myConnection.Open(); MySqlTransaction myTrans = myConnection.BeginTransaction(); string mySelectQuery = "SELECT * FROM myTable"; MySqlCommand myCommand = new MySqlCommand(mySelectQuery, myConnection,myTrans); myCommand.CommandTimeout = 20; }
public: void CreateMySqlCommand() { MySqlConnection* myConnection = new MySqlConnection(S"Persist Security Info=False; database=test;server=myServer"); myConnection->Open(); MySqlTransaction* myTrans = myConnection->BeginTransaction(); String* mySelectQuery = S"SELECT * FROM myTable"; MySqlCommand* myCommand = new MySqlCommand(mySelectQuery, myConnection, myTrans); myCommand->CommandTimeout = 20; };
Initializes a new instance of the MySqlCommand class.
The base constructor initializes all fields to their default values. The following table shows initial property values for an instance of .
Properties
Initial Value
empty string ("")
0
CommandType.Text
Null

You can change the value for any of these properties through a separate call to the property.

The following example creates a and sets some of its properties.

Public Sub CreateMySqlCommand() Dim myCommand As New MySqlCommand() myCommand.CommandType = CommandType.Text End Sub
public void CreateMySqlCommand() { MySqlCommand myCommand = new MySqlCommand(); myCommand.CommandType = CommandType.Text; }
Initializes a new instance of the class with the text of the query.
The text of the query.
When an instance of is created, the following read/write properties are set to initial values.

Properties
Initial Value
cmdText
0
CommandType.Text
Null

You can change the value for any of these properties through a separate call to the property.

The following example creates a and sets some of its properties.

Public Sub CreateMySqlCommand() Dim sql as String = "SELECT * FROM mytable" Dim myCommand As New MySqlCommand(sql) myCommand.CommandType = CommandType.Text End Sub
public void CreateMySqlCommand() { string sql = "SELECT * FROM mytable"; MySqlCommand myCommand = new MySqlCommand(sql); myCommand.CommandType = CommandType.Text; }
Initializes a new instance of the class with the text of the query and a .
The text of the query.
A that represents the connection to an instance of SQL Server.
When an instance of is created, the following read/write properties are set to initial values.

Properties
Initial Value
cmdText
0
CommandType.Text
connection

You can change the value for any of these properties through a separate call to the property.

The following example creates a and sets some of its properties.

Public Sub CreateMySqlCommand() Dim conn as new MySqlConnection("server=myServer") Dim sql as String = "SELECT * FROM mytable" Dim myCommand As New MySqlCommand(sql, conn) myCommand.CommandType = CommandType.Text End Sub
public void CreateMySqlCommand() { MySqlConnection conn = new MySqlConnection("server=myserver") string sql = "SELECT * FROM mytable"; MySqlCommand myCommand = new MySqlCommand(sql, conn); myCommand.CommandType = CommandType.Text; }
Initializes a new instance of the class with the text of the query, a , and the .
The text of the query.
A that represents the connection to an instance of SQL Server.
The in which the executes.
When an instance of is created, the following read/write properties are set to initial values.

Properties
Initial Value
cmdText
0
CommandType.Text
connection

You can change the value for any of these properties through a separate call to the property.

The following example creates a and sets some of its properties.

Public Sub CreateMySqlCommand() Dim conn as new MySqlConnection("server=myServer") conn.Open(); Dim txn as MySqlTransaction = conn.BeginTransaction() Dim sql as String = "SELECT * FROM mytable" Dim myCommand As New MySqlCommand(sql, conn, txn) myCommand.CommandType = CommandType.Text End Sub
public void CreateMySqlCommand() { MySqlConnection conn = new MySqlConnection("server=myserver") conn.Open(); MySqlTransaction txn = conn.BeginTransaction(); string sql = "SELECT * FROM mytable"; MySqlCommand myCommand = new MySqlCommand(sql, conn, txn); myCommand.CommandType = CommandType.Text; }
Executes a SQL statement against the connection and returns the number of rows affected.
Number of rows affected
You can use ExecuteNonQuery to perform any type of database operation, however any resultsets returned will not be available. Any output parameters used in calling a stored procedure will be populated with data and can be retrieved after execution is complete. For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. For all other types of statements, the return value is -1.
The following example creates a MySqlCommand and then executes it using ExecuteNonQuery. The example is passed a string that is a SQL statement (such as UPDATE, INSERT, or DELETE) and a string to use to connect to the data source. `Public Sub CreateMySqlCommand(myExecuteQuery As String, myConnection As MySqlConnection) Dim myCommand As New MySqlCommand(myExecuteQuery, myConnection) myCommand.Connection.Open() myCommand.ExecuteNonQuery() myConnection.Close() End Sub` `public void CreateMySqlCommand(string myExecuteQuery, MySqlConnection myConnection) { MySqlCommand myCommand = new MySqlCommand(myExecuteQuery, myConnection); myCommand.Connection.Open(); myCommand.ExecuteNonQuery(); myConnection.Close(); }`
Sends the to the Connection, and builds a using one of the values.
One of the values.

When the property is set to StoredProcedure, the property should be set to the name of the stored procedure. The command executes this stored procedure when you call ExecuteReader.

The supports a special mode that enables large binary values to be read efficiently. For more information, see the SequentialAccess setting for .

While the is in use, the associated is busy serving the MySqlDataReader. While in this state, no other operations can be performed on the MySqlConnection other than closing it. This is the case until the method of the MySqlDataReader is called. If the MySqlDataReader is created with CommandBehavior set to CloseConnection, closing the MySqlDataReader closes the connection automatically.

When calling ExecuteReader with the SingleRow behavior, you should be aware that using a limit clause in your SQL will cause all rows (up to the limit given) to be retrieved by the client. The method will still return false after the first row but pulling all rows of data into the client will have a performance impact. If the limit clause is not necessary, it should be avoided.

A object.
Sends the to the Connection and builds a .
A object.

When the property is set to StoredProcedure, the property should be set to the name of the stored procedure. The command executes this stored procedure when you call ExecuteReader.

While the is in use, the associated is busy serving the MySqlDataReader. While in this state, no other operations can be performed on the MySqlConnection other than closing it. This is the case until the method of the MySqlDataReader is called.

The following example creates a , then executes it by passing a string that is a SQL SELECT statement, and a string to use to connect to the data source. `Public Sub CreateMySqlDataReader(mySelectQuery As String, myConnection As MySqlConnection) Dim myCommand As New MySqlCommand(mySelectQuery, myConnection) myConnection.Open() Dim myReader As MySqlDataReader myReader = myCommand.ExecuteReader() Try While myReader.Read() Console.WriteLine(myReader.GetString(0)) End While Finally myReader.Close myConnection.Close End Try End Sub` `public void CreateMySqlDataReader(string mySelectQuery, MySqlConnection myConnection) { MySqlCommand myCommand = new MySqlCommand(mySelectQuery, myConnection); myConnection.Open(); MMySqlDataReader myReader; myReader = myCommand.ExecuteReader(); try { while(myReader.Read()) { Console.WriteLine(myReader.GetString(0)); } } finally { myReader.Close(); myConnection.Close(); } }`
Creates a prepared version of the command on an instance of MySQL Server.

Prepared statements are only supported on MySQL version 4.1 and higher. Calling prepare while connected to earlier versions of MySQL will succeed but will execute the statement in the same way as unprepared.

The following example demonstrates the use of the Prepare method. `public sub PrepareExample() Dim cmd as New MySqlCommand("INSERT INTO mytable VALUES (@val)", myConnection) cmd.Parameters.Add( "@val", 10 ) cmd.Prepare() cmd.ExecuteNonQuery() cmd.Parameters(0).Value = 20 cmd.ExecuteNonQuery() end sub` `private void PrepareExample() { MySqlCommand cmd = new MySqlCommand("INSERT INTO mytable VALUES (@val)", myConnection); cmd.Parameters.Add( "@val", 10 ); cmd.Prepare(); cmd.ExecuteNonQuery(); cmd.Parameters[0].Value = 20; cmd.ExecuteNonQuery(); }`
Executes the query, and returns the first column of the first row in the result set returned by the query. Extra columns or rows are ignored.
The first column of the first row in the result set, or a null reference if the result set is empty

Use the ExecuteScalar method to retrieve a single value (for example, an aggregate value) from a database. This requires less code than using the method, and then performing the operations necessary to generate the single value using the data returned by a

The following example creates a and then executes it using ExecuteScalar. The example is passed a string that is a SQL statement that returns an aggregate result, and a string to use to connect to the data source.

Public Sub CreateMySqlCommand(myScalarQuery As String, myConnection As MySqlConnection) Dim myCommand As New MySqlCommand(myScalarQuery, myConnection) myCommand.Connection.Open() myCommand.ExecuteScalar() myConnection.Close() End Sub
public void CreateMySqlCommand(string myScalarQuery, MySqlConnection myConnection) { MySqlCommand myCommand = new MySqlCommand(myScalarQuery, myConnection); myCommand.Connection.Open(); myCommand.ExecuteScalar(); myConnection.Close(); }
public: void CreateMySqlCommand(String* myScalarQuery, MySqlConnection* myConnection) { MySqlCommand* myCommand = new MySqlCommand(myScalarQuery, myConnection); myCommand->Connection->Open(); myCommand->ExecuteScalar(); myConnection->Close(); }
Gets or sets the SQL statement to execute at the data source.
The SQL statement or stored procedure to execute. The default is an empty string.

When the property is set to StoredProcedure, the CommandText property should be set to the name of the stored procedure. The user may be required to use escape character syntax if the stored procedure name contains any special characters. The command executes this stored procedure when you call one of the Execute methods. Starting with Connector/Net 5.0, having both a stored function and stored procedure with the same name in the same database is not supported. It is suggested that you provide unqiue names for your stored routines.

The following example creates a and sets some of its properties. `Public Sub CreateMySqlCommand() Dim myCommand As New MySqlCommand() myCommand.CommandText = "SELECT * FROM Mytable ORDER BY id" myCommand.CommandType = CommandType.Text End Sub` `public void CreateMySqlCommand() { MySqlCommand myCommand = new MySqlCommand(); myCommand.CommandText = "SELECT * FROM mytable ORDER BY id"; myCommand.CommandType = CommandType.Text; }`
Gets or sets the wait time before terminating the attempt to execute a command and generating an error.
The time (in seconds) to wait for the command to execute. The default is 30 seconds.
CommandTimeout is dependent on the ability of MySQL to cancel an executing query. Because of this, CommandTimeout is only supported when connected to MySQL version 5.0.0 or higher.
Gets or sets a value indicating how the property is to be interpreted.
One of the values. The default is Text.

When you set the CommandType property to StoredProcedure, you should set the property to the name of the stored procedure. The command executes this stored procedure when you call one of the Execute methods.

The following example creates a and sets some of its properties. `Public Sub CreateMySqlCommand() Dim myCommand As New MySqlCommand() myCommand.CommandType = CommandType.Text End Sub` `public void CreateMySqlCommand() { MySqlCommand myCommand = new MySqlCommand(); myCommand.CommandType = CommandType.Text; }`
Gets or sets the used by this instance of the .
The connection to a data source. The default value is a null reference (Nothing in Visual Basic).

If you set Connection while a transaction is in progress and the property is not null, an is generated. If the Transaction property is not null and the transaction has already been committed or rolled back, Transaction is set to null.

The following example creates a and sets some of its properties. `Public Sub CreateMySqlCommand() Dim mySelectQuery As String = "SELECT * FROM mytable ORDER BY id" Dim myConnectString As String = "Persist Security Info=False;database=test;server=myServer" Dim myCommand As New MySqlCommand(mySelectQuery) myCommand.Connection = New MySqlConnection(myConnectString) myCommand.CommandType = CommandType.Text End Sub` `public void CreateMySqlCommand() { string mySelectQuery = "SELECT * FROM mytable ORDER BY id"; string myConnectString = "Persist Security Info=False;database=test;server=myServer"; MySqlCommand myCommand = new MySqlCommand(mySelectQuery); myCommand.Connection = new MySqlConnection(myConnectString); myCommand.CommandType = CommandType.Text; }`
Provides the id of the last inserted row.
Id of the last inserted row. -1 if none exists.
An important point to remember is that this property can be used in batch SQL scenarios but it's important to remember that it will only reflect the insert id from the last insert statement in the batch.

This property can also be used when the batch includes select statements and ExecuteReader is used. This property can be consulted during result set processing.
Get the
The parameters of the SQL statement or stored procedure. The default is an empty collection.
Connector/Net does not support unnamed parameters. Every parameter added to the collection must have an associated name.
The following example creates a and displays its parameters. To accomplish this, the method is passed a , a query string that is a SQL SELECT statement, and an array of objects. `Public Sub CreateMySqlCommand(myConnection As MySqlConnection, _ mySelectQuery As String, myParamArray() As MySqlParameter) Dim myCommand As New MySqlCommand(mySelectQuery, myConnection) myCommand.CommandText = "SELECT id, name FROM mytable WHERE age=@age" myCommand.UpdatedRowSource = UpdateRowSource.Both myCommand.Parameters.Add(myParamArray) Dim j As Integer For j = 0 To myCommand.Parameters.Count - 1 myCommand.Parameters.Add(myParamArray(j)) Next j Dim myMessage As String = "" Dim i As Integer For i = 0 To myCommand.Parameters.Count - 1 myMessage += myCommand.Parameters(i).ToString() & ControlChars.Cr Next i Console.WriteLine(myMessage) End Sub` `public void CreateMySqlCommand(MySqlConnection myConnection, string mySelectQuery, MySqlParameter[] myParamArray) { MySqlCommand myCommand = new MySqlCommand(mySelectQuery, myConnection); myCommand.CommandText = "SELECT id, name FROM mytable WHERE age=@age"; myCommand.Parameters.Add(myParamArray); for (int j=0; j<myParamArray.Length; j++) { myCommand.Parameters.Add(myParamArray[j]) ; } string myMessage = ""; for (int i = 0; i < myCommand.Parameters.Count; i++) { myMessage += myCommand.Parameters[i].ToString() + "\n"; } MessageBox.Show(myMessage); }`
Gets or sets the within which the executes.
The . The default value is a null reference (Nothing in Visual Basic).
You cannot set the Transaction property if it is already set to a specific value, and the command is in the process of executing. If you set the transaction property to a object that is not connected to the same as the object, an exception will be thrown the next time you attempt to execute a statement.
Gets or sets how command results are applied to the when used by the method of the .
One of the values.

The default value is Both unless the command is automatically generated (as in the case of the ), in which case the default is None.