Export from SQL Server to json text file using PowerShell - json

Question

You should read this if: you are trying to find out how to transform SQL server data into JSON and put it into a text .json file
Question:
Can someone tell me what's wrong with this code? My goal is to read data from a SQL Server table, convert it to JSON and then save the result as a JSON text file. The code runs but the resulting .json file just has:
{
"FieldCount": 11
},
{
repeated over and over again and nothing more.
My code:
$instance = "localhost\SQLEXPRESS"
$connectionString = "Server=$Instance; Database=myDB;Integrated Security=True;"
$query = "Select * from myTable"
$connection = New-Object System.Data.SqlClient.SqlConnection
$connection.ConnectionString = $connectionString
$connection.Open()
$command = $connection.CreateCommand()
$command.CommandText = $query
$result = $command.ExecuteReader()
$result | ConvertTo-Json | Out-File "file.json"
$connection.Close()
Update:
Will award the answer to postanote as technically he/she answered my original question (although I will caveat and say I have not tried it).
However I would recommend either Mike's answer or what I eventually ended up going with, using BCP:
bcp "select * from myTable FOR JSON AUTO" queryout "C:\filepath\testsml.json" -c -S ".\SQLEXPRESS" -d myDBName -T
Note that the JSON AUTO will automatically come up with a json scehma for you vs. JSON pipeline which allows you to customize it.
You have to install BCP first:
https://learn.microsoft.com/en-us/sql/tools/bcp-utility?view=sql-server-2017

Answer 1

If you are using sql server express 2016 or later you should be able to do it on the database side using FOR JSON clause. Try something like
$instance = "localhost\SQLEXPRESS"
$connectionString = "Server=$Instance; Database=myDB;Integrated Security=True;"
$query = "Select * from myTable FOR JSON AUTO"
$connection = New-Object System.Data.SqlClient.SqlConnection
$connection.ConnectionString = $connectionString
$connection.Open()
$command = $connection.CreateCommand()
$command.CommandText = $query
$command.ExecuteScalar() | Out-File "file.json"

Answer 2

Try something like this …
### Exporting SQL Server table to JSON
Clear-Host
#--Establishing connection to SQL Server --#
$InstanceName = "."
$connectionString = "Server=$InstanceName;Database=msdb;Integrated Security=True;"
#--Main Query --#
$query = "SELECT * FROM sysjobs"
$connection = New-Object System.Data.SqlClient.SqlConnection
$connection.ConnectionString = $connectionString
$connection.Open()
$command = $connection.CreateCommand()
$command.CommandText = $query
$result = $command.ExecuteReader()
$table = new-object "System.Data.DataTable"
$table.Load($result)
#--Exporting data to the screen --#
$table | select $table.Columns.ColumnName | ConvertTo-Json
$connection.Close()
# Results
{
"job_id": "5126aca3-1003-481c-ab36-60b45a7ee757",
"originating_server_id": 0,
"name": "syspolicy_purge_history",
"enabled": 1,
"description": "No description available.",
"start_step_id": 1,
"category_id": 0,
"owner_sid": [
1
],
"notify_level_eventlog": 0,
"notify_level_email": 0,
"notify_level_netsend": 0,
"notify_level_page": 0,
"notify_email_operator_id": 0,
"notify_netsend_operator_id": 0,
"notify_page_operator_id": 0,
"delete_level": 0,
"date_created": "\/Date(1542859767703)\/",
"date_modified": "\/Date(1542859767870)\/",
"version_number": 5
}

Answer 3

The "rub" here is that the SQL command FOR JSON AUTO even with execute scalar, will truncate JSON output, and outputting to a variable with VARCHAR(max) will still truncate. Using SQL 2016 LocalDB bundled with Visual Studio if that matters.