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Update column.md
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@ -232,6 +232,7 @@ ALTER TABLE table_with_ttl MODIFY COLUMN column_ttl REMOVE TTL;
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Materializes or updates a column with an expression for a default value (`DEFAULT` or `MATERIALIZED`).
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It is used if it is necessary to add or update a column with a complicated expression, because evaluating such an expression directly on `SELECT` executing turns out to be expensive.
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Implemented as a [mutation](/docs/en/sql-reference/statements/alter/index.md#mutations).
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Syntax:
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