ISqlWhereBuilder.WhereIsNull(string left) Method

.NET Standard 2.x

Creates a WHERE clause, and adds a search condition to the WHERE clause. Uses IS NULL operator to search for values that are null.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  ISqlWhereAndOr WhereIsNull(string left);

Parameters

left System.String

A SQL expression on the left of the IS NULL operator.

Returns

SnapObjects.Data.ISqlWhereAndOr

Returns the ISqlWhereAndOr object which can be used to add more search conditions to the current WHERE clause.

Examples

The following code example uses the AndWhereIsNotNull method to specify that data retrieved from the "Course" table must have a null value for Title.

using SnapObjects.Data;
using System;

namespace Appeon.ApiDoc.ISqlWhereBuilderExamples
{
    public class WhereIsNullExample
    {
        private readonly SchoolContext _context;

        public WhereIsNullExample(SchoolContext dataContext)
        {
            // Sets data context.
            _context = dataContext;
        }

        public void Example()
        {

            // Declares SqlQueryBuilder.
            var sqlbuilder = new SqlQueryBuilder();

            // Defines a SQL statement, and sets the WhereIsNull condition: Title must be null.            
            sqlbuilder.Select("*")
                .From("Course")
                .WhereIsNull("Title");

            string sql = sqlbuilder.ToSqlString(_context);

            Console.WriteLine(sql);

            /*This code produces the following output:

            SELECT
            *
            FROM [Course]
            WHERE ([Title] IS NULL)
           */
        }
    }
}

Applies to

.NET Standard

2.x