ClickHouse/docs/en/sql-reference/table-functions/merge.md
2024-02-24 08:02:13 +08:00

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---
slug: /en/sql-reference/table-functions/merge
sidebar_position: 130
sidebar_label: merge
---
# merge
Creates a temporary [Merge](../../engines/table-engines/special/merge.md) table. The table structure is taken from the first table encountered that matches the regular expression.
**Syntax**
```sql
merge(['db_name',] 'tables_regexp')
```
**Arguments**
- `db_name` — Possible values (optional, default is `currentDatabase()`):
- database name,
- constant expression that returns a string with a database name, for example, `currentDatabase()`,
- `REGEXP(expression)`, where `expression` is a regular expression to match the DB names.
- `tables_regexp` — A regular expression to match the table names in the specified DB or DBs.
**See Also**
- [Merge](../../engines/table-engines/special/merge.md) table engine