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Update type-conversion-functions.md
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@ -13,7 +13,7 @@ incompatible datatypes (for example from `String` to `Int`). Make sure to check
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ClickHouse generally uses the [same behavior as C++ programs](https://en.cppreference.com/w/cpp/language/implicit_conversion).
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`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.
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`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).
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Example:
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@ -26,6 +26,15 @@ SELECT
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┌─source_type────────────┬─to_type_result_type────┬─cast_result_type─┐
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│ LowCardinality(String) │ LowCardinality(String) │ String │
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└────────────────────────┴────────────────────────┴──────────────────┘
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SELECT
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toTypeName(toNullable('') AS val) AS source_type,
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toTypeName(toString(val)) AS to_type_result_type,
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toTypeName(CAST(val, 'String')) AS cast_result_type
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┌─source_type──────┬─to_type_result_type─┬─cast_result_type─┐
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│ Nullable(String) │ Nullable(String) │ String │
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└──────────────────┴─────────────────────┴──────────────────┘
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```
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## toInt(8\|16\|32\|64\|128\|256)
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