ISqlJoinBuilder.LeftJoinRaw(string joinClause, string builderAlias) Method

.NET Standard 2.x

Uses the LEFT OUTER JOIN operator to join the original table source directly with a raw SQL to create a joined table. You need to specify an alias for the raw SQL.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  ISqlJoinOnBuilder LeftJoinRaw(string joinClause, string builderAlias);

Parameters

joinClause System.String

A string of raw SQL after the LEFT OUTER JOIN keyword.

builderAlias System.String

The alias for the raw SQL.

Returns

SnapObjects.Data.ISqlJoinOnBuilder

Returns an ISqlJoinOnBuilder object that can be used to create the condition on which the join is based.

Examples

The following code example joins one table with another using the LeftJoinRaw method.

using SnapObjects.Data;
using System;

namespace Appeon.ApiDoc.ISqlJoinBuilderExamples
{
    public class LeftJoinRawExample
    {
        private readonly SchoolContext _context;

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

        public void Example2()
        {
            var sqlQueryBuilder = new SqlQueryBuilder();

            // Defines a query (named as "C"), and gets the count of courses in each department from the "Course" table.
            // Gets DepartmentID values and Name values from the "Department" table, and CourseCount values from query C.
            // Sets the condition to join the "Department" table and the derived table: 
            // Department.DepartmentID = C.DepartmentID.             
            sqlQueryBuilder
                .Select("Department.DepartmentID")
                .Select("Department.Name")
                .Select("C.CourseCount")
                .From("Department")
                .LeftJoinRaw("(Select DepartmentID, count(1) as CourseCount From " +
                    "Course  group by DepartmentID ) C " +
                    "On Department.DepartmentID = C.DepartmentID"
                    , "Course");

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

            Console.WriteLine(sql);
            
            /*This code example produces the following output:           
              SELECT
                [Department].[DepartmentID],
                [Department].[Name],
                [C].[CourseCount]
              FROM [Department]
              Left JOIN (SELECT
                            [DepartmentID],
                            COUNT(1) AS [CourseCount]
                         FROM [Course]
                         GROUP BY
                            [DepartmentID] ) [C]
              ON [Department].[DepartmentID] = [C].[DepartmentID]
            */
        }
    }
}

Applies to

.NET Standard

2.x