MartijnVisser commented on a change in pull request #18813:
URL: https://github.com/apache/flink/pull/18813#discussion_r823697352
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File path: docs/content/docs/dev/table/types.md
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@@ -1487,6 +1481,88 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined pair `from` type and `target`
type pair. While some
+casting operations can always succeed regardless of the input value, others
can fail at runtime
+(i.e. where there is no way to create a value for the target type). For
example, it is always
+possible to convert `INT` to `STRING`, but you cannot always convert a
`STRING` to `INT`.
+
+During the planning stage, Flink SQL rejects queries for invalid cast input
and target type with
+a `ValidationException`, e.g. when trying to cast a `TIMESTAMP` to an
`INTERVAL`.
+While for valid type pairs that can fail at runtime Flink SQL accepts them,
but requires the user to correctly handle failures.
+
+In Flink SQL, casting can be performed by using one of the two following
built-in functions:
Review comment:
```suggestion
In Flink Table API and SQL, casting can be performed by using one of the two
following built-in functions:
```
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