59 lines
1.4 KiB
Plaintext
59 lines
1.4 KiB
Plaintext
[[null-value]]
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=== `null_value`
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A `null` value cannot be indexed or searched. When a field is set to `null`,
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(or an empty array or an array of `null` values) it is treated as though that
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field has no values.
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The `null_value` parameter allows you to replace explicit `null` values with
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the specified value so that it can be indexed and searched. For instance:
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[source,js]
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--------------------------------------------------
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PUT my_index
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{
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"mappings": {
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"my_type": {
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"properties": {
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"status_code": {
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"type": "string",
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"index": "not_analyzed",
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"null_value": "NULL" <1>
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}
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}
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}
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}
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}
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PUT my_index/my_type/1
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{
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"status_code": null
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}
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PUT my_index/my_type/2
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{
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"status_code": [] <2>
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}
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GET my_index/_search
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{
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"query": {
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"term": {
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"status_code": "NULL" <3>
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}
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}
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}
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--------------------------------------------------
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// AUTOSENSE
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<1> Replace explicit `null` values with the term `NULL`.
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<2> An empty array does not contain an explicit `null`, and so won't be replaced with the `null_value`.
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<3> A query for `NULL` returns document 1, but not document 2.
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IMPORTANT: The `null_value` needs to be the same datatype as the field. For
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instance, a `long` field cannot have a string `null_value`. String fields
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which are `analyzed` will also pass the `null_value` through the configured
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analyzer.
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Also see the <<query-dsl-missing-query,`missing` query>> for its `null_value` support.
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