如何获得一个可空的DateTime值?

Question

我的SQLite数据库包含一个可空的DateTime字段，我必须在PowerShell中读取。我的select查询:

$colId = "myPrimaryKeyColumn"
$col1 = "myColumnName"
$select = "SELECT CAST($col1 as nvarchar(20)) FROM $table ORDER BY $colId DESC LIMIT 1"

返回CAST(Alive as nvarchar(20)) : 04/11/2022 17:17:15。如何得到只是04/11/2022 17:17:15部分?

I tried:

Invoke-SqliteQuery -SQLiteConnection $con -Query $select | Where-Object { $_.$col1}
Invoke-SqliteQuery -SQLiteConnection $con -Query $select -As DataRow | Where-Object { $_.$col1}
Invoke-SqliteQuery -SQLiteConnection $con -Query $select -As PSObject| Where-Object { $_.$col1}

输出空行。

Answer 1

您需要使用-As SingleValue(您不需要Where-Object)

Invoke-SqliteQuery -SQLiteConnection $con -Query $select -As SingleValue