EXCHANGE | ClickHouse Docs

Exchanges the names of two tables or dictionaries atomically. This task can also be accomplished with a RENAME query using a temporary name, but the operation is not atomic in that case.

Syntax

EXCHANGE TABLES|DICTIONARIES [db0.]name_A AND [db1.]name_B [ON CLUSTER cluster]

EXCHANGE TABLES

Exchanges the names of two tables.

Syntax

EXCHANGE TABLES [db0.]table_A AND [db1.]table_B [ON CLUSTER cluster]

EXCHANGE MULTIPLE TABLES

You can exchange multiple table pairs in a single query by separating them with commas.

Example

Querysql

-- Create tables
CREATE TABLE a (a UInt8) ENGINE=Memory;
CREATE TABLE b (b UInt8) ENGINE=Memory;
CREATE TABLE c (c UInt8) ENGINE=Memory;
CREATE TABLE d (d UInt8) ENGINE=Memory;

-- Exchange two pairs of tables in one query
EXCHANGE TABLES a AND b, c AND d;

SHOW TABLE a;
SHOW TABLE b;
SHOW TABLE c;
SHOW TABLE d;

Responsesql

-- Now table 'a' has the structure of 'b', and table 'b' has the structure of 'a'
┌─statement──────────────┐
│ CREATE TABLE default.a↴│
│↳(                     ↴│
│↳    `b` UInt8         ↴│
│↳)                     ↴│
│↳ENGINE = Memory        │
└────────────────────────┘
┌─statement──────────────┐
│ CREATE TABLE default.b↴│
│↳(                     ↴│
│↳    `a` UInt8         ↴│
│↳)                     ↴│
│↳ENGINE = Memory        │
└────────────────────────┘

-- Now table 'c' has the structure of 'd', and table 'd' has the structure of 'c'
┌─statement──────────────┐
│ CREATE TABLE default.c↴│
│↳(                     ↴│
│↳    `d` UInt8         ↴│
│↳)                     ↴│
│↳ENGINE = Memory        │
└────────────────────────┘
┌─statement──────────────┐
│ CREATE TABLE default.d↴│
│↳(                     ↴│
│↳    `c` UInt8         ↴│
│↳)                     ↴│
│↳ENGINE = Memory        │
└────────────────────────┘

EXCHANGE DICTIONARIES

Exchanges the names of two dictionaries.

Syntax

EXCHANGE DICTIONARIES [db0.]dict_A AND [db1.]dict_B [ON CLUSTER cluster]

See Also

Dictionaries