Library Written in C# For Parsing SQL Server T-SQL Scripts in .Net 

PostgreSQL Tutorial Full Course 2022

I provide here in this PostgreSQL tutorial a full course you can use to master PostgreSQL. Postgres is an object relational database that is just as fast as MySQL that adheres more closely to SQL standards and excels at concurrency. Postgres is also superior at avoiding data corruption.

TABLE OF CONTENTS
00:00 Intro
00:30 Why Use Postgres?
01:13 What is a Database
03:12 Change Database Theme
03:53 Create a Database
04:46 Design a Database
05:50 Turn Invoice into a Database
07:04 Make a Table
12:13 Data Types
16:36 Adding Data to Table
18:15 To See Data
18:25 SELECT
19:19 Create Custom Type
20:48 Change Column Data Type
22:58 Thinking About Tables
25:37 Breaking Up Tables
27:03  Primary & Foreign Keys
32:40 Foreign & Primary Keys
33:28 Altering Tables Many Examples
53:00 Getting Data from One Table
53:40 Where
54:30 Conditional Operators
55:48 Logical Operators
58:12 Order By
59:32 Limit
1:01:45 GROUP BY
1:03:11 Distinct
1:05:00 Getting Data from Multiple Tables
1:05:21 Inner Join
1:08:50 Join 3 Tables
1:13:15  Arithmetic Operators
1:13:45 Join with Where
1:14:55 Outer Joins
1:17:03 Cross Joins
1:18:16 Unions
1:19:27 Extract
1:21:05 IS NULL
1:22:03 SIMILAR LIKE & ~
1:29:25 GROUP BY
1:31:14  HAVING
1:32:18  AGGREGATE FUNCTIONS
1:34:22 WORKING WITH VIEWS
1:45:01 SQL Functions
1:49:00 Dollar Quotes
1:50:06 Functions that Return Void
1:52:38 Get Maximum Product Price
1:53:39 Get Total Value of Inventory
1:54:26 Get Number of Customers
1:56:15 Named Parameters
2:01:30 Return a Row / Composite
2:03:38 Get Multiple Rows
2:07:08 PL/pgSQL
2:11:35 Variables in Functions
2:15:55 Store Rows in Variables
2:19:17 IN INOUT and OUT
2:21:01 Using Multiple Outs
2:25:56 Return Query Results
2:33:42 IF ELSEIF and ELSE
2:38:48  CASE Statement
2:42:01 Loop Statement
2:45:20 FOR LOOP
2:48:34 Result Sets, Blocks & Raise Notice
2:51:11 For Each and Arrays
2:53:20 While Loop
2:54:54 Continue
3:01:34 Stored Procedures
3:09:35 Triggers
3:29:25 Cursors
3:39:45 Installation 

 var query = Enumerable.Range(1, 5).Select(number => number);
var observableQuery = query.ToObservable();
var observer = Observer.Create<int>(onNext: number => Console.WriteLine(number));
observableQuery.Subscribe(observer);

 var observableValue1 = Observable.Return("Value");
var observableValue2 = Observable.Return(2);

        public static IObservable<T> Return<T>(T value)
        {
            return Observable.Create<T>(o =>
            {
                o.OnNext(value);
                o.OnCompleted();
                return Disposable.Empty;
            });
        }

 var observableValue1 = Observable.Return<string>("Value");
var observableValue2 = Observable.Return<int>(2);

 var emptyObservable = Observable.Empty<string>();

        public static IObservable<T> Empty<T>()
        {
            return Observable.Create<T>(o =>
            {
                o.OnCompleted();
                return Disposable.Empty;
            });
        }

 var neverObservable = Observable.Never<string>();

        public static IObservable<T> Never<T>()
        {
            return Observable.Create<T>(o =>
            {
                return Disposable.Empty;
            });
        }

 var throwObservable = Observable.Throw<string>(new Exception());

        public static IObservable<T> Throws<T>(Exception exception)
        {
            return Observable.Create<T>(o =>
            {
                o.OnError(exception);
                return Disposable.Empty;
            });
        }

 var range = Observable.Range(10, 15);
range.Subscribe(Console.WriteLine, () => Console.WriteLine("Completed"));

        public static IObservable<int> Range(int start, int count)
        {
            var max = start + count;
            return Observable.Generate(
                initialState: start,
                condition: value => value < max,
                iterate: value => value + 1,
                resultSelector: value => value);
        }

 var interval = Observable.Interval(period: TimeSpan.FromMilliseconds(250));
interval.Subscribe(Console.WriteLine, () => Console.WriteLine("completed"));

 var timer = Observable.Timer(dueTime: TimeSpan.FromSeconds(1));
 timer.Subscribe(Console.WriteLine, () => Console.WriteLine("completed"));

        static void StartAction()
        {
            var start = Observable.Start(() =>
            {
                Console.Write("Observable.Start");
                for (int i = 0; i < 10; i++)
                {
                    Thread.Sleep(100);
                    Console.Write(".");
                }
            });
            start.Subscribe(
               onNext: unit => Console.WriteLine("published"),
               onCompleted: () => Console.WriteLine("completed"));
        }

        static void StartFunc()
        {
            var start = Observable.Start(() =>
            {
                Console.Write("Observable.Start");
                for (int i = 0; i < 10; i++)
                {
                    Thread.Sleep(100);
                    Console.Write(".");
                }
                return "value";
            });
            start.Subscribe(
               onNext: Console.WriteLine,
               onCompleted: () => Console.WriteLine("completed"));
        }

 var items = new System.Collections.ObjectModel.ObservableCollection<string>
  {
          "Item1", "Item2", "Item3"
  };

            items.CollectionChanged += (sender, ea) =>
            {
                if (ea.Action == NotifyCollectionChangedAction.Remove)
                {
                    foreach (var oldItem in ea.OldItems.Cast<string>())
                    {
                        Console.WriteLine("Removed {0}", oldItem);
                    }
                }
            };

            var removals =
                Observable.FromEventPattern<NotifyCollectionChangedEventHandler, NotifyCollectionChangedEventArgs>
                (
                    addHandler: handler => items.CollectionChanged += handler,
                    removeHandler: handler => items.CollectionChanged -= handler
                )
                .Where(e => e.EventArgs.Action == NotifyCollectionChangedAction.Remove)
                .SelectMany(c => c.EventArgs.OldItems.Cast<string>());

            var disposable = removals.Subscribe(onNext: item => Console.WriteLine("Removed {0}", item));

 items.Remove("Item1");

 var task = Task.Factory.StartNew(() => "Test");
var source = task.ToObservable();
source.Subscribe(Console.WriteLine, () => Console.WriteLine("completed"));

 PM> Install-Package Rxx

 using (new FileStream("file.txt", FileMode.Open)
                 .ReadToEndObservable()
                 .Subscribe(x => Console.WriteLine(x.Length)))
{
         Console.ReadKey();
}

@page "/"

@page "/"

<p>Hello, @name</p>

@code
{
    string name = "Vahid N.";
}

 <p>Hello, @name.ToUpper()</p>

@page "/"

<p>Hello, @name.ToUpper()</p>
<p>Hello, @CustomToUpper(name)</p>

@code
{
    string name = "Vahid N.";

    string CustomToUpper(string value) => value.ToUpper();
}

<p>Let's add 2 + 2 : @2 + 2 </p>

<p>Let's add 2 + 2 : @(2 + 2) </p>

<button @onclick="@(()=>Console.WriteLine("Test"))">Click me</button>

@page "/"

<button @onclick="@WriteLog">Click me 2</button>

@code
{
    void WriteLog()
    {
        Console.WriteLine("Test");
    }
}

@page "/"

<button @onclick="@(()=>WriteLogWithParam("Test 3"))">Click me 3</button>

@code
{
    void WriteLogWithParam(string value)
    {
        Console.WriteLine(value);
    }
}

BlazorRazorSample\Client\Pages\Index.razor(12,25): error CS1501: No overload for method 'WriteLog' takes 1 arguments

@page "/"

<p>Hello, @StringUtils.MyCustomToUpper(name)</p>

@code
{
    public class StringUtils
    {
        public static string MyCustomToUpper(string value) => value.ToUpper();
    }
}

namespace BlazorRazorSample.Shared
{
    public class StringUtils
    {
        public static string MyNewCustomToUpper(string value) => value.ToUpper();
    }
}

@page "/"

@using BlazorRazorSample.Shared

<p>Hello, @StringUtils.MyNewCustomToUpper(name)</p>

@using BlazorRazorSample.Shared

using System;

namespace BlazorRazorSample.Shared.Models
{
    public class MovieDto
    {
        public string Title { set; get; }

        public DateTime ReleaseDate { set; get; }
    }
}

@using BlazorRazorSample.Shared.Models

@page "/"

<div>
    <h3>Movies</h3>
    @foreach(var movie in movies)
    {
        <p>Title: <b>@movie.Title</b></p>
        <p>ReleaseDate: @movie.ReleaseDate.ToString("dd MMM yyyy")</p>
    }
</div>

@code
{
    List<MovieDto> movies = new List<MovieDto>
    {
        new MovieDto
        {
            Title = "Movie 1",
            ReleaseDate = DateTime.Now.AddYears(-1)
        },
        new MovieDto
        {
            Title = "Movie 2",
            ReleaseDate = DateTime.Now.AddYears(-2)
        },
        new MovieDto
        {
            Title = "Movie 3",
            ReleaseDate = DateTime.Now.AddYears(-3)
        }
    };
}

    @for(var i = 0; i < movies.Count; i++)
    {
        <div style="background-color: @(i % 2 == 0 ? "blue" : "red")">
            <p>Title: <b>@movies[i].Title</b></p>
            <p>ReleaseDate: @movies[i].ReleaseDate.ToString("dd MMM yyyy")</p>
        </div>
    }

@page "/fetchdata"
@using BlazorRazorSample.Shared
@inject HttpClient Http

<h1>Weather forecast</h1>

<p>This component demonstrates fetching data from the server.</p>

@if (forecasts == null)
{
    <p><em>Loading...</em></p>
}
else
{
    <table class="table">
        <thead>
            <tr>
                <th>Date</th>
                <th>Temp. (C)</th>
                <th>Temp. (F)</th>
                <th>Summary</th>
            </tr>
        </thead>
        <tbody>
            @foreach (var forecast in forecasts)
            {
                <tr>
                    <td>@forecast.Date.ToShortDateString()</td>
                    <td>@forecast.TemperatureC</td>
                    <td>@forecast.TemperatureF</td>
                    <td>@forecast.Summary</td>
                </tr>
            }
        </tbody>
    </table>
}

@code {
    private WeatherForecast[] forecasts;

    protected override async Task OnInitializedAsync()
    {
        forecasts = await Http.GetFromJsonAsync<WeatherForecast[]>("WeatherForecast");
    }

}

@if (forecasts == null)
{
    <p><em>Loading...</em></p>
}

new MovieDto
{
   Title = "<i>Movie 1</i>",
   ReleaseDate = DateTime.Now.AddYears(-1)
},

<p>Title: <b>@((MarkupString)movie.Title)</b></p>

SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty,
       FIRST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID
       ORDER BY SalesOrderDetailID RANGE BETWEEN UNBOUNDED PRECEDING  AND UNBOUNDED FOLLOWING)  LstValue
FROM Test_First_Last_Value s
     WHERE SalesOrderID IN (43670, 43669, 43667, 43663)
     ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty
     
SELECT s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty,
       LAST_VALUE(SalesOrderDetailID) OVER (PARTITION BY SalesOrderID
       ORDER BY SalesOrderDetailID DESC RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)  LstValue
FROM Test_First_Last_Value s
     WHERE SalesOrderID IN (43670, 43669, 43667, 43663)
     ORDER BY s.SalesOrderID,s.SalesOrderDetailID,s.OrderQty

Set up a Redis backplane for ASP.NET Core multi-node deployments, using the built-in Rate Limiting support that's part of .NET 7.