$cond operator should allow $match as a boolean expression

XMLWordPrintableJSON

    • Query Execution
    • Fully Compatible
    • None
    • None
    • None
    • None
    • None
    • None
    • None

      When using $cond in projections, it would be useful to have $match as a boolean expression.

      Use Case:

       
db.objects.aggregate([
	{
		$match: { status: "active" }
	}, {
		$project: {
			name: 1,
			meta: 1,
			tags: 1,
			score: {
				$add: [
					{
						$cond:[{
							$match: { tags: "a tag I like" }
						}, 100, 0]
					}, {
						$cond:[{
							$match: { tags: "a tag I really like" }
						}, 250, 0]
					}, {
						$cond:[{
							$match: { tags: "a tag I dislike" }
						}, -100, 0]
					}, {
						$cond:[{
							$match: { "meta.promoted": true }
						}, 1000, 0]
					}
				]
			}
		}
	},{
		$match: { score: { $gt: 0 } }
	}
])

      This would eliminate the need to add other $cond expressions like $in (SERVER-6146)

            Assignee:
            [DO NOT USE] Backlog - Query Execution
            Reporter:
            Dillon Krug
            Votes:
            3 Vote for this issue
            Watchers:
            12 Start watching this issue

              Created:
              Updated: