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33776045f6
Add docs for the `to_xxx()` conversion functions. --------- Co-authored-by: Abdon Pijpelink <abdon.pijpelink@elastic.co>
52 lines
1.5 KiB
Text
52 lines
1.5 KiB
Text
[[esql-to_datetime]]
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=== `TO_DATETIME`
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Converts an input value to a date value.
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The input can be a single- or multi-valued field or an expression. The input
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type must be of a string or numeric type.
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A string will only be successfully converted if it's respecting the format
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`yyyy-MM-dd'T'HH:mm:ss.SSS'Z'`. For example:
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[source,esql]
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----
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include::{esql-specs}/date.csv-spec[tag=to_datetime-str]
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----
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returns:
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[%header,format=dsv,separator=|]
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|===
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include::{esql-specs}/date.csv-spec[tag=to_datetime-str-result]
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|===
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Note that in this example, the last value in the source multi-valued
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field has not been converted. The reason being that if the date format is not
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respected, the conversion will result in a *null* value. When this happens a
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_Warning_ header is added to the response. The header will provide information
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on the source of the failure:
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`"Line 1:112: evaluation of [TO_DATETIME(string)] failed, treating result as null. Only first 20 failures recorded."`
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A following header will contain the failure reason and the offending value:
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`"java.lang.IllegalArgumentException: failed to parse date field [1964-06-02 00:00:00] with format [yyyy-MM-dd'T'HH:mm:ss.SSS'Z']"`
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If the input parameter is of a numeric type, its value will be interpreted as
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milliseconds since the https://en.wikipedia.org/wiki/Unix_time[Unix epoch].
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For example:
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[source,esql]
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----
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include::{esql-specs}/date.csv-spec[tag=to_datetime-int]
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----
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returns:
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[%header,format=dsv,separator=|]
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|===
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include::{esql-specs}/date.csv-spec[tag=to_datetime-int-result]
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|===
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Alias: TO_DT
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