matriv commented on a change in pull request #18813:
URL: https://github.com/apache/flink/pull/18813#discussion_r808858592
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -191,6 +155,34 @@ For the Python Table API, those types are available in
`pyflink.table.types.Data
{{< /tab >}}
{{< /tabs >}}
+The default planner supports the following set of SQL types:
+
+| Data Type | Remarks for Data Type |
+|:-----------------|:---------------------------------------------------|
+| `CHAR` | |
+| `VARCHAR` | |
+| `STRING` | |
+| `BOOLEAN` | |
+| `BYTES` | `BINARY` and `VARBINARY` are not supported yet. |
Review comment:
Is this correct about BINARY & VARBINARY?
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
Review comment:
```suggestion
that is, for some input values there is no way to create a value for the
target type.
```
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
+For example, it's always possible to convert `INT` to `STRING`, but viceversa
is not true,
+as you can provide an input `STRING` which cannot be converted to `INT`, like
`'abc'`.
+
+Flink SQL validates and rejects queries which cast tuples are invalid,
+e.g. when trying to cast a `TIMESTAMP` to an `INTERVAL`,
+but the user needs to handle manually cases where a cast tuple is valid, but
can fail at runtime.
+
+In Flink SQL casting can be performed using one of the two following built-in
functions:
+
+* `CAST`: The regular cast function defined by the SQL standard. It can fail
the job if the cast operation is fallible and the provided input is not valid.
The type inference will preserve the nullability of the input type.
+* `TRY_CAST`: An extension to the regular cast function which returns `NULL`
in case the cast operation fails. Its return type is always nullable.
+
+For example:
+
+```sql
+CAST('42' AS INT) --- returns 42 of type VARCHAR NOT NULL
Review comment:
```suggestion
CAST('42' AS INT) --- returns 42 of type INT NOT NULL
```
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
Review comment:
Maybe before this, add a sentence to explain what you have later on, and
make it more clear:
`ValidationExceptions` for unsupported tuples (I actually prefer the word
`pairs` in this context),
and runtime exceptions when the tuple is supported but certain runtime input
values cannot be casted.
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
Review comment:
either `between a from type and a target type`, or `for a defined
tuple...`.
`between a tuple` sounds weird to me.
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
+For example, it's always possible to convert `INT` to `STRING`, but viceversa
is not true,
+as you can provide an input `STRING` which cannot be converted to `INT`, like
`'abc'`.
+
+Flink SQL validates and rejects queries which cast tuples are invalid,
+e.g. when trying to cast a `TIMESTAMP` to an `INTERVAL`,
+but the user needs to handle manually cases where a cast tuple is valid, but
can fail at runtime.
+
+In Flink SQL casting can be performed using one of the two following built-in
functions:
+
+* `CAST`: The regular cast function defined by the SQL standard. It can fail
the job if the cast operation is fallible and the provided input is not valid.
The type inference will preserve the nullability of the input type.
+* `TRY_CAST`: An extension to the regular cast function which returns `NULL`
in case the cast operation fails. Its return type is always nullable.
+
+For example:
+
+```sql
+CAST('42' AS INT) --- returns 42 of type VARCHAR NOT NULL
+CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+CAST('non-number' AS INT) --- throws an exception and fails the job
+
+TRY_CAST('42' AS INT) --- returns 42 of type VARCHAR
Review comment:
```suggestion
TRY_CAST('42' AS INT) --- returns 42 of type INT
```
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
+For example, it's always possible to convert `INT` to `STRING`, but viceversa
is not true,
+as you can provide an input `STRING` which cannot be converted to `INT`, like
`'abc'`.
+
+Flink SQL validates and rejects queries which cast tuples are invalid,
+e.g. when trying to cast a `TIMESTAMP` to an `INTERVAL`,
+but the user needs to handle manually cases where a cast tuple is valid, but
can fail at runtime.
+
+In Flink SQL casting can be performed using one of the two following built-in
functions:
+
+* `CAST`: The regular cast function defined by the SQL standard. It can fail
the job if the cast operation is fallible and the provided input is not valid.
The type inference will preserve the nullability of the input type.
+* `TRY_CAST`: An extension to the regular cast function which returns `NULL`
in case the cast operation fails. Its return type is always nullable.
+
+For example:
+
+```sql
+CAST('42' AS INT) --- returns 42 of type VARCHAR NOT NULL
+CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+CAST('non-number' AS INT) --- throws an exception and fails the job
+
+TRY_CAST('42' AS INT) --- returns 42 of type VARCHAR
+TRY_CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+TRY_CAST('non-number' AS INT) --- returns NULL of type INT
+COALESCE(TRY_CAST('non-number' AS INT), 0) --- returns 0 of type INT NOT NULL
+```
+
+The matrix below describes the supported cast tuples, where "Y" means
supported, "!" means fallible, "N" means unsupported:
+
+| From\Target |
`CHAR`¹/<br/>`VARCHAR`¹/<br/>`STRING` |
`BINARY`¹/<br/>`VARBINARY`¹/<br/>`BYTES` | `BOOLEAN` | `DECIMAL` | `TINYINT` |
`SMALLINT` | `INTEGER` | `BIGINT` | `FLOAT` | `DOUBLE` | `DATE` | `TIME` |
`TIMESTAMP` | `TIMESTAMP_LTZ` | `INTERVAL` | `ARRAY` | `MULTISET` | `MAP` |
`ROW` | `RAW` | `STRUCTURED` |
+|:---------------------------------------|:-------------------------------------:|:----------------------------------------:|:---------:|:---------:|:---------:|:----------:|:---------:|:--------:|:-------:|:--------:|:------:|:------:|:-----------:|:---------------:|:----------:|:-------:|:----------:|:-----:|:-----:|:-----:|:------------:|
+| `CHAR`/<br/>`VARCHAR`/<br/>`STRING` | Y
| ! | ! | ! | !
| ! | ! | ! | ! | ! | ! | ! |
! | ! | N | N | N | N | N
| N | N |
+| `BINARY`/<br/>`VARBINARY`/<br/>`BYTES` | Y
| Y | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | N |
+| `BOOLEAN` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DECIMAL` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `TINYINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `SMALLINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `INTEGER` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁵ | N | N | N | N
| N | N |
+| `BIGINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁶ | N | N | N | N
| N | N |
+| `FLOAT` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DOUBLE` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DATE` | Y
| N | N | N | N
| N | N | N | N | N | Y | N |
Y | Y | N | N | N | N | N
| N | N |
+| `TIME` | Y
| N | N | N | N
| N | N | N | N | N | N | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP_LTZ` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `INTERVAL` | Y
| N | N | N | N
| N | Y⁵ | Y⁶ | N | N | N | N |
N | N | Y | N | N | N | N
| N | N |
+| `ARRAY` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | !³ | N | N | N
| N | N |
+| `MULTISET` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | !³ | N | N
| N | N |
+| `MAP` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | !³ | N
| N | N |
+| `ROW` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | !³
| N | N |
+| `RAW` | Y
| ! | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| Y⁴ | N |
+| `STRUCTURED` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | !³ |
+
+1. All the casting to constant length or variable length will also trim and
pad accordingly to the type definition.
+2. `TO_TIMESTAMP` and `TO_TIMESTAMP_LTZ` must be used instead of
`CAST`/`TRY_CAST`.
+3. Supported iff the children type tuples are supported. Fallible iff the
children type tuples are fallible.
Review comment:
iff you mean, if and only if?
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
+For example, it's always possible to convert `INT` to `STRING`, but viceversa
is not true,
+as you can provide an input `STRING` which cannot be converted to `INT`, like
`'abc'`.
+
+Flink SQL validates and rejects queries which cast tuples are invalid,
+e.g. when trying to cast a `TIMESTAMP` to an `INTERVAL`,
+but the user needs to handle manually cases where a cast tuple is valid, but
can fail at runtime.
+
+In Flink SQL casting can be performed using one of the two following built-in
functions:
+
+* `CAST`: The regular cast function defined by the SQL standard. It can fail
the job if the cast operation is fallible and the provided input is not valid.
The type inference will preserve the nullability of the input type.
+* `TRY_CAST`: An extension to the regular cast function which returns `NULL`
in case the cast operation fails. Its return type is always nullable.
+
+For example:
+
+```sql
+CAST('42' AS INT) --- returns 42 of type VARCHAR NOT NULL
+CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+CAST('non-number' AS INT) --- throws an exception and fails the job
+
+TRY_CAST('42' AS INT) --- returns 42 of type VARCHAR
+TRY_CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+TRY_CAST('non-number' AS INT) --- returns NULL of type INT
+COALESCE(TRY_CAST('non-number' AS INT), 0) --- returns 0 of type INT NOT NULL
+```
+
+The matrix below describes the supported cast tuples, where "Y" means
supported, "!" means fallible, "N" means unsupported:
+
+| From\Target |
`CHAR`¹/<br/>`VARCHAR`¹/<br/>`STRING` |
`BINARY`¹/<br/>`VARBINARY`¹/<br/>`BYTES` | `BOOLEAN` | `DECIMAL` | `TINYINT` |
`SMALLINT` | `INTEGER` | `BIGINT` | `FLOAT` | `DOUBLE` | `DATE` | `TIME` |
`TIMESTAMP` | `TIMESTAMP_LTZ` | `INTERVAL` | `ARRAY` | `MULTISET` | `MAP` |
`ROW` | `RAW` | `STRUCTURED` |
+|:---------------------------------------|:-------------------------------------:|:----------------------------------------:|:---------:|:---------:|:---------:|:----------:|:---------:|:--------:|:-------:|:--------:|:------:|:------:|:-----------:|:---------------:|:----------:|:-------:|:----------:|:-----:|:-----:|:-----:|:------------:|
+| `CHAR`/<br/>`VARCHAR`/<br/>`STRING` | Y
| ! | ! | ! | !
| ! | ! | ! | ! | ! | ! | ! |
! | ! | N | N | N | N | N
| N | N |
+| `BINARY`/<br/>`VARBINARY`/<br/>`BYTES` | Y
| Y | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | N |
+| `BOOLEAN` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DECIMAL` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `TINYINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `SMALLINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `INTEGER` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁵ | N | N | N | N
| N | N |
+| `BIGINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁶ | N | N | N | N
| N | N |
+| `FLOAT` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DOUBLE` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DATE` | Y
| N | N | N | N
| N | N | N | N | N | Y | N |
Y | Y | N | N | N | N | N
| N | N |
+| `TIME` | Y
| N | N | N | N
| N | N | N | N | N | N | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP_LTZ` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `INTERVAL` | Y
| N | N | N | N
| N | Y⁵ | Y⁶ | N | N | N | N |
N | N | Y | N | N | N | N
| N | N |
+| `ARRAY` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | !³ | N | N | N
| N | N |
+| `MULTISET` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | !³ | N | N
| N | N |
+| `MAP` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | !³ | N
| N | N |
+| `ROW` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | !³
| N | N |
+| `RAW` | Y
| ! | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| Y⁴ | N |
+| `STRUCTURED` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | !³ |
+
+1. All the casting to constant length or variable length will also trim and
pad accordingly to the type definition.
+2. `TO_TIMESTAMP` and `TO_TIMESTAMP_LTZ` must be used instead of
`CAST`/`TRY_CAST`.
+3. Supported iff the children type tuples are supported. Fallible iff the
children type tuples are fallible.
+4. Supported iff the `RAW` class and serializer are equals
+5. Supported iff `INTERVAL` is a `MONTH TO YEAR` range
+5. Supported iff `INTERVAL` is a `DAY TO TIME` range
+
+Also note that a cast of a `NULL` value will always return `NULL`, no matter
the function used is `CAST` or `TRY_CAST`.
+
+### Legacy casting
+
+Pre Flink 1.15 casting behaviour can be enabled by setting
`table.exec.legacy-cast-behaviour` to `enabled`.
Review comment:
We need to say that this is enabled by default.
##########
File path: docs/content/docs/dev/table/types.md
##########
@@ -1487,6 +1479,86 @@ Not supported.
{{< /tab >}}
{{< /tabs >}}
+Casting
+-------
+
+Flink SQL can perform casting between a defined tuple `from` type and `target`
type.
+While some casting operations can always succeed no matter the input value,
others can fail at runtime,
+that is for some input values there is no way to construct an instance of the
target type.
+For example, it's always possible to convert `INT` to `STRING`, but viceversa
is not true,
+as you can provide an input `STRING` which cannot be converted to `INT`, like
`'abc'`.
+
+Flink SQL validates and rejects queries which cast tuples are invalid,
+e.g. when trying to cast a `TIMESTAMP` to an `INTERVAL`,
+but the user needs to handle manually cases where a cast tuple is valid, but
can fail at runtime.
+
+In Flink SQL casting can be performed using one of the two following built-in
functions:
+
+* `CAST`: The regular cast function defined by the SQL standard. It can fail
the job if the cast operation is fallible and the provided input is not valid.
The type inference will preserve the nullability of the input type.
+* `TRY_CAST`: An extension to the regular cast function which returns `NULL`
in case the cast operation fails. Its return type is always nullable.
+
+For example:
+
+```sql
+CAST('42' AS INT) --- returns 42 of type VARCHAR NOT NULL
+CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+CAST('non-number' AS INT) --- throws an exception and fails the job
+
+TRY_CAST('42' AS INT) --- returns 42 of type VARCHAR
+TRY_CAST(NULL AS VARCHAR) --- returns NULL of type VARCHAR
+TRY_CAST('non-number' AS INT) --- returns NULL of type INT
+COALESCE(TRY_CAST('non-number' AS INT), 0) --- returns 0 of type INT NOT NULL
+```
+
+The matrix below describes the supported cast tuples, where "Y" means
supported, "!" means fallible, "N" means unsupported:
+
+| From\Target |
`CHAR`¹/<br/>`VARCHAR`¹/<br/>`STRING` |
`BINARY`¹/<br/>`VARBINARY`¹/<br/>`BYTES` | `BOOLEAN` | `DECIMAL` | `TINYINT` |
`SMALLINT` | `INTEGER` | `BIGINT` | `FLOAT` | `DOUBLE` | `DATE` | `TIME` |
`TIMESTAMP` | `TIMESTAMP_LTZ` | `INTERVAL` | `ARRAY` | `MULTISET` | `MAP` |
`ROW` | `RAW` | `STRUCTURED` |
+|:---------------------------------------|:-------------------------------------:|:----------------------------------------:|:---------:|:---------:|:---------:|:----------:|:---------:|:--------:|:-------:|:--------:|:------:|:------:|:-----------:|:---------------:|:----------:|:-------:|:----------:|:-----:|:-----:|:-----:|:------------:|
+| `CHAR`/<br/>`VARCHAR`/<br/>`STRING` | Y
| ! | ! | ! | !
| ! | ! | ! | ! | ! | ! | ! |
! | ! | N | N | N | N | N
| N | N |
+| `BINARY`/<br/>`VARBINARY`/<br/>`BYTES` | Y
| Y | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | N |
+| `BOOLEAN` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DECIMAL` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `TINYINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `SMALLINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | N | N | N | N | N
| N | N |
+| `INTEGER` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁵ | N | N | N | N
| N | N |
+| `BIGINT` | Y
| N | Y | Y | Y
| Y | Y | Y | Y | Y | N | N |
N² | N² | Y⁶ | N | N | N | N
| N | N |
+| `FLOAT` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DOUBLE` | Y
| N | N | Y | Y
| Y | Y | Y | Y | Y | N | N |
N | N | N | N | N | N | N
| N | N |
+| `DATE` | Y
| N | N | N | N
| N | N | N | N | N | Y | N |
Y | Y | N | N | N | N | N
| N | N |
+| `TIME` | Y
| N | N | N | N
| N | N | N | N | N | N | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `TIMESTAMP_LTZ` | Y
| N | N | N | N
| N | N | N | N | N | Y | Y |
Y | Y | N | N | N | N | N
| N | N |
+| `INTERVAL` | Y
| N | N | N | N
| N | Y⁵ | Y⁶ | N | N | N | N |
N | N | Y | N | N | N | N
| N | N |
+| `ARRAY` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | !³ | N | N | N
| N | N |
+| `MULTISET` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | !³ | N | N
| N | N |
+| `MAP` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | !³ | N
| N | N |
+| `ROW` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | !³
| N | N |
+| `RAW` | Y
| ! | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| Y⁴ | N |
+| `STRUCTURED` | Y
| N | N | N | N
| N | N | N | N | N | N | N |
N | N | N | N | N | N | N
| N | !³ |
+
+1. All the casting to constant length or variable length will also trim and
pad accordingly to the type definition.
+2. `TO_TIMESTAMP` and `TO_TIMESTAMP_LTZ` must be used instead of
`CAST`/`TRY_CAST`.
+3. Supported iff the children type tuples are supported. Fallible iff the
children type tuples are fallible.
+4. Supported iff the `RAW` class and serializer are equals
+5. Supported iff `INTERVAL` is a `MONTH TO YEAR` range
+5. Supported iff `INTERVAL` is a `DAY TO TIME` range
+
+Also note that a cast of a `NULL` value will always return `NULL`, no matter
the function used is `CAST` or `TRY_CAST`.
+
+### Legacy casting
+
+Pre Flink 1.15 casting behaviour can be enabled by setting
`table.exec.legacy-cast-behaviour` to `enabled`.
+In particular, this will:
+
+* Disable trimming/padding for casting to `CHAR`/`VARCHAR`/`BINARY`/`VARBINARY`
+* `CAST` never fails but returns `NULL`, behaving as `TRY_CAST` but without
inferring the correct type
+* Formatting of some casting to `CHAR`/`VARCHAR`/`STRING` produces slightly
different results.
+
+{{< hint warning >}}
+We **discourage** the use of this flag and we **strongly suggest** for new
projects to always use the new casting behaviour.
Review comment:
We need to `strongly suggest` to use `DISABLED` for the flag, as it's by
default `ENABLED`.
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