使用Powershell从MSSQL数据库获取行数

Question

I'm trying to get the number of rows from a Microsoft SQL database table in Powershell as an integer and am stuck peeling the figure out of the object Powershell is returning.

I have;

$SQLServer = "MSSQL01"   $SQLDBName = "TheTable" $SqlQuery = "select count(*) from cases where opened_date =< '2014-07-30'"

$SqlConnection = New-Object System.Data.SqlClient.SqlConnection $SqlConnection.ConnectionString = "Server = $SQLServer; Database = $SQLDBName; Integrated Security = True"

$SqlCmd = New-Object System.Data.SqlClient.SqlCommand $SqlCmd.CommandText = $SqlQuery $SqlCmd.Connection = $SqlConnection

$SqlAdapter = New-Object System.Data.SqlClient.SqlDataAdapter $SqlAdapter.SelectCommand = $SqlCmd

$DataSet = New-Object System.Data.DataSet $SqlAdapter.Fill($DataSet)

$SqlConnection.Close()

Now $DataSet.Tables[0] in this instance returns an object like;

Table Name
-----------

45

How can I grab just the 45 as an int?

Answer 1

Look at ExecuteScalar :

$SQLServer = "MSSQL01"   
$SQLDBName = "TheTable" 
$SqlQuery = "select count(*) from cases where opened_date =< '2014-07-30'"
$SqlConnection = New-Object System.Data.SqlClient.SqlConnection 
$SqlConnection.ConnectionString = "Server = $SQLServer; Database = $SQLDBName; Integrated Security = True"
$SqlCmd = New-Object System.Data.SqlClient.SqlCommand $SqlCmd.CommandText = $SqlQuery $SqlCmd.Connection = $SqlConnection
$SqlConnection.Open() 
$Rows= [Int32]$SqlCmd.ExecuteScalar()
$SqlConnection.Close()

Answer 2

Here's a version which provides two encapsulated functions, based on @jessehouwing's answer. This also handles an optional port, choice of TrustedAuth vs. User/Passwd Authentication, and an optional WHERE clause.

function createSqlConnection($sqlServer, $sqlPort, $dbName, $user, $password) {
    $sqlConnection = New-Object System.Data.SqlClient.sqlConnection
    if ($sqlPort) { $sqlServer = "$sqlServer,$sqlPort" }
    if ($user -and $password) {
        $sqlConnection.ConnectionString = "Server=$sqlServer; Database=$dbName; User Id=$user; Password=$password"
    } else {
        $sqlConnection.ConnectionString = "Server=$sqlServer; Database=$dbName; Integrated Security=True"
    }

    return $sqlConnection
}

function getRowCount($sqlConnection, $table, $where = "1=1") {
    $sqlQuery = "SELECT count(*) FROM $table WHERE $where"
    $sqlConnection.Open()
    $SqlCmd = New-Object System.Data.SqlClient.SqlCommand($sqlQuery, $sqlConnection)
    $row_count = [Int32] $SqlCmd.ExecuteScalar()
    $sqlConnection.Close()
    return $row_count
}

To use it:

$dbConn = createSqlConnection 'db-server' $null 'myDatabase' $user $password
$count = getRowCount $dbConn 'the_table'

Answer 3

Using ExecuteScalar is a much better solution. If, for some reason, you want to stick with the DataSet use either:

$DataSet.Tables[0].'Table Name'

or

$DataSet.Tables[0] | Select-Object -ExpandProperty "Table Name"