ISqlWhereAndOr<TBuilder>.OrWhereExists(ISqlBuilder sqlBuilder) Method

.NET Standard 2.x

Adds the OR logical operator and a search condition to the WHERE clause; and uses EXISTS to test for the existence of the record returned from a subquery.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  TBuilder OrWhereExists(ISqlBuilder sqlBuilder);

Parameters

sqlBuilder SnapObjects.Data.ISqlBuilder

An ISqlBuilder object which represents a SQL subquery on the right of the EXISTS operator.

Returns

TBuilder

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

Examples

The following code example demonstrates how to use the OrWhereExists method to add an OR EXISTS condition to the WHERE clause. In this example, the EXISTS condition specifies that the data must exist in the result set of a subquery.

using SnapObjects.Data;
using System;

namespace Appeon.ApiDoc.ISqlWhereAndOrExamples
{
    public class OrWhereExistsExample
    {
        private readonly SchoolContext _context;

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

        public void Example()
        {

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

            // Defines a subquery.
            var deptsql = new SqlQueryBuilder();
            deptsql.Select("DepartmentID")
                .From("Department", "d")
                .Where("d.DepartmentID", "c.DepartmentID")
                .AndWhere("d.Name", SqlBuilder.Parameter<string>("id"));

            // Defines a SQL statement, and adds an OR EXISTS condition: 
            // the data must exist in the result set of the subquery.
            sqlbuilder.Select("Title")
                .From("Course", "c")
                .Where("CourseID", SqlBinaryOperator.GreaterThan,
                        SqlBuilder.Parameter<int>("courid"))
                .OrWhereExists(deptsql);

            string sql = sqlbuilder.ToSqlString(_context);

            Console.WriteLine(sql);

            /*This code produces the following output:

            SELECT
            [Title]
            FROM [Course] AS [c]
            WHERE ([CourseID] > @courid
            OR EXISTS (SELECT
            [DepartmentID]
            FROM [Department] AS [d]
            WHERE ([d].[DepartmentID] = [c].[DepartmentID]
            AND [d].[Name] = @id)))
           */
        }
    }
}

Applies to

.NET Standard

2.x