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QueryBuilder.LeftOuterJoin<'Outer,'Q,'Inner,'Key,'Result> Method (F#)

Den Delimarsky|Last Updated: 8/18/2017
1 Contributor

A query operator that correlates two sets of selected values based on matching keys and groups the results. If any group is empty, a group with a single default value is used instead. Normal usage is leftOuterJoin (for y in elements2 -> key1 = key2) into group.

Namespace/Module Path: Microsoft.FSharp.Linq

Assembly: FSharp.Core (in FSharp.Core.dll)


// Signature:
member this.LeftOuterJoin : QuerySource<'Outer,'Q> * QuerySource<'Inner,'Q> * ('Outer -> 'Key) * ('Inner -> 'Key) * ('Outer -> seq<'Inner> -> 'Result) -> QuerySource<'Result,'Q>

// Usage:
queryBuilder.LeftOuterJoin (outerSource, innerSource, outerKeySelector, innerKeySelector, resultSelector)


outerSource Type: QuerySource<'Outer,'Q>

The outer query.

innerSource Type: QuerySource<'Inner,'Q>

The inner query.

outerKeySelector Type: 'Outer -> 'Key

A function to select the correlation key from the outer query.

innerKeySelector Type: 'Inner -> 'Key

A function to select the correlation key from the inner query.

resultSelector Type: 'Outer -> seq<'Inner> -> 'Result

A function to select the resulting elements.

Return Value

The resulting query.


For more information and examples, see Query Expressions (F#).


Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

Version Information

F# Core Library Versions

Supported in: 4.0, Portable

See Also

Linq.QueryBuilder Class (F#)

Microsoft.FSharp.Linq Namespace (F#)

Query Expressions (F#)

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