ISqlQueryBuilder.UnionAll(ISqlQueryBuilder queryBuilder) Method

.NET Standard 2.x

Uses UNION ALL to combine the result set of the current SQL SELECT statement and the result set of another SQL SELECT statement generated by the ISqlQueryBuilder object. The combined result set includes duplicate records.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  ISqlQueryBuilder UnionAll(ISqlQueryBuilder queryBuilder);

Parameters

queryBuilder SnapObjects.Data.ISqlQueryBuilder

The ISqlQueryBuilder object which represents a SQL query whose result set is to be combined with the result set of the current SQL query.

Returns

SnapObjects.Data.ISqlQueryBuilder

Returns the current ISqlQueryBuilder object.

Remarks

The result sets to be combined must have the same number of columns and the same data type of these columns, and the order of these columns in the SELECT statement must be the same.

Examples

The following code example demonstrates how to use the UnionAll(ISqlQueryBuilder queryBuilder) method to merge the result sets of two or more SQL SELECT statements; it includes duplicate rows and does not sort the data. These SELECT statements must have the same number of columns of the same data type and in the same selected order.

using SnapObjects.Data;
using System;

namespace Appeon.ApiDoc.ISqlQueryBuilderExamples
{
    public class UnionAllExample
    {
        private SchoolContext _context;

        public UnionAllExample(SchoolContext dataContext)
        {
            // Sets Data Context.
            _context = dataContext;
        }

        public void Example1()
        {

            // Declares SqlQueryBuilder.
            var sqlbuilder1 = new SqlQueryBuilder();
            var sqlbuilder2 = new SqlQueryBuilder();

            sqlbuilder1.Select("courseid", "courseid")
                .Select("location", "address")
                .From("OnsiteCourse", "onsite");

            sqlbuilder2.Select("courseid", "courseid")
                .Select("url", "address")
                .From("OnlineCourse", "online");

            // Merges the statement of sqlbuilder2 with sqlbuilder1.
            sqlbuilder2.UnionAll (sqlbuilder1);

            // Converts to raw SQL for the database corresponding to the data context.
            string sql = sqlbuilder2.ToSqlString(_context);

            Console.WriteLine(sql);
            
            /*This code produces the following output:
            
            SELECT
            [courseid] AS [courseid],
            [url] AS [address]
            FROM [OnlineCourse] AS [online]
            UNION ALL
            (SELECT
            [courseid] AS [courseid],
            [location] AS [address]
            FROM [OnsiteCourse] AS [onsite])
            */
        }
    }
}

Applies to

.NET Standard

2.x