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143 lines
3.0 KiB
Markdown
143 lines
3.0 KiB
Markdown
---
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slug: /en/sql-reference/statements/drop
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sidebar_position: 44
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sidebar_label: DROP
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---
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# DROP Statements
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Deletes existing entity. If the `IF EXISTS` clause is specified, these queries do not return an error if the entity does not exist. If the `SYNC` modifier is specified, the entity is dropped without delay.
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## DROP DATABASE
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Deletes all tables inside the `db` database, then deletes the `db` database itself.
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Syntax:
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``` sql
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DROP DATABASE [IF EXISTS] db [ON CLUSTER cluster] [SYNC]
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```
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## DROP TABLE
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Deletes one or more tables.
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:::tip
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To undo the deletion of a table, please see [UNDROP TABLE](/docs/en/sql-reference/statements/undrop.md)
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:::
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Syntax:
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``` sql
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DROP [TEMPORARY] TABLE [IF EXISTS] [IF EMPTY] [db1.]name_1[, [db2.]name_2, ...] [ON CLUSTER cluster] [SYNC]
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```
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Limitations:
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- If the clause `IF EMPTY` is specified, the server checks the emptiness of the table only on the replica which received the query.
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- Deleting multiple tables at once is not an atomic operation, i.e. if the deletion of a table fails, subsequent tables will not be deleted.
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## DROP DICTIONARY
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Deletes the dictionary.
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Syntax:
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``` sql
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DROP DICTIONARY [IF EXISTS] [db.]name [SYNC]
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```
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## DROP USER
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Deletes a user.
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Syntax:
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``` sql
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DROP USER [IF EXISTS] name [,...] [ON CLUSTER cluster_name] [FROM access_storage_type]
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```
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## DROP ROLE
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Deletes a role. The deleted role is revoked from all the entities where it was assigned.
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Syntax:
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``` sql
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DROP ROLE [IF EXISTS] name [,...] [ON CLUSTER cluster_name] [FROM access_storage_type]
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```
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## DROP ROW POLICY
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Deletes a row policy. Deleted row policy is revoked from all the entities where it was assigned.
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Syntax:
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``` sql
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DROP [ROW] POLICY [IF EXISTS] name [,...] ON [database.]table [,...] [ON CLUSTER cluster_name] [FROM access_storage_type]
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```
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## DROP QUOTA
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Deletes a quota. The deleted quota is revoked from all the entities where it was assigned.
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Syntax:
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``` sql
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DROP QUOTA [IF EXISTS] name [,...] [ON CLUSTER cluster_name] [FROM access_storage_type]
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```
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## DROP SETTINGS PROFILE
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Deletes a settings profile. The deleted settings profile is revoked from all the entities where it was assigned.
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Syntax:
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``` sql
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DROP [SETTINGS] PROFILE [IF EXISTS] name [,...] [ON CLUSTER cluster_name] [FROM access_storage_type]
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```
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## DROP VIEW
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Deletes a view. Views can be deleted by a `DROP TABLE` command as well but `DROP VIEW` checks that `[db.]name` is a view.
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Syntax:
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``` sql
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DROP VIEW [IF EXISTS] [db.]name [ON CLUSTER cluster] [SYNC]
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```
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## DROP FUNCTION
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Deletes a user defined function created by [CREATE FUNCTION](./create/function.md).
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System functions can not be dropped.
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**Syntax**
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``` sql
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DROP FUNCTION [IF EXISTS] function_name [on CLUSTER cluster]
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```
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**Example**
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``` sql
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CREATE FUNCTION linear_equation AS (x, k, b) -> k*x + b;
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DROP FUNCTION linear_equation;
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```
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## DROP NAMED COLLECTION
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Deletes a named collection.
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**Syntax**
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``` sql
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DROP NAMED COLLECTION [IF EXISTS] name [on CLUSTER cluster]
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```
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**Example**
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``` sql
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CREATE NAMED COLLECTION foobar AS a = '1', b = '2';
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DROP NAMED COLLECTION foobar;
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```
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