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Update type-conversion-functions.md

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Denny Crane 2023-03-29 15:33:07 -03:00 committed by GitHub
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11
docs/en/sql-reference/functions/type-conversion-functions.md
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@ -13,7 +13,7 @@ incompatible datatypes (for example from `String` to `Int`). Make sure to check
ClickHouse generally uses the [same behavior as C++ programs](https://en.cppreference.com/w/cpp/language/implicit_conversion).
`to<type>` functions and [cast](#castx-t) have different behaviour in some cases, for example in case of [LowCardinality](../data-types/lowcardinality.md): [cast](#castx-t) removes [LowCardinality](../data-types/lowcardinality.md) trait `to<type>` functions don't.
`to<type>` functions and [cast](#castx-t) have different behaviour in some cases, for example in case of [LowCardinality](../data-types/lowcardinality.md): [cast](#castx-t) removes [LowCardinality](../data-types/lowcardinality.md) trait `to<type>` functions don't. The same with [Nullable](../data-types/nullable).
Example:
@ -26,6 +26,15 @@ SELECT
┌─source_type────────────┬─to_type_result_type────┬─cast_result_type─┐
│ LowCardinality(String) │ LowCardinality(String) │ String │
└────────────────────────┴────────────────────────┴──────────────────┘
SELECT
toTypeName(toNullable('') AS val) AS source_type,
toTypeName(toString(val)) AS to_type_result_type,
toTypeName(CAST(val, 'String')) AS cast_result_type
┌─source_type──────┬─to_type_result_type─┬─cast_result_type─┐
│ Nullable(String) │ Nullable(String) │ String │
└──────────────────┴─────────────────────┴──────────────────┘
```
## toInt(8\|16\|32\|64\|128\|256)