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Type:
Bug
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Resolution: Works as Designed
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Priority:
Minor - P4
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None
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Affects Version/s: None
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Component/s: Query Planning
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None
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Query Optimization
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ALL
This restriction is counter-intuitive and makes little sense:
| <field>:<0 or false> | Specifies the exclusion of a field. To exclude a field conditionally, use the REMOVE variable instead. For details, see Exclude Fields Conditionally. If you specify the exclusion of a field other than _id, you cannot employ any other $project specification forms. This restriction does not apply to conditionally exclusion of a field using the REMOVE variable. See also the $unset stage to exclude fields. |
> db.sample2.aggregate([{$project: {i1:1, str1:0}}])
Error: command failed: {
"ok" : 0,
"errmsg" : "Invalid $project :: caused by :: Cannot do exclusion on field str1 in inclusion projection",
"code" : 31254,
...