Add REPLACE query desc

docs/en/engines/database-engines/atomic.md

@@ -0,0 +1,15 @@
+---
+toc_priority: 32
+toc_title: Atomic
+---
+
+
+# Atomic {#atomic}
+
+It is an experimental database engine, it supports non-blocking `DROP` and `RENAME TABLE` queries and atomic `EXCHANGE TABLES t1 AND t2` queries.
+
+## Creating a Database {#creating-a-database}
+
+    CREATE DATABASE test ENGINE = Atomic;
+
+[Original article](https://clickhouse.tech/docs/en/engines/database_engines/atomic/) <!--hide-->

docs/en/engines/database-engines/index.md

@@ -18,4 +18,6 @@ You can also use the following database engines:
 
 -   [MaterializeMySQL](../../engines/database-engines/materialize-mysql.md)
 
+-   [Atomic](../../engines/database-engines/atomic.md)
+
 [Original article](https://clickhouse.tech/docs/en/database_engines/) <!--hide-->

docs/en/sql-reference/statements/create/table.md

@@ -14,7 +14,7 @@ By default, tables are created only on the current server. Distributed DDL queri
 ### With Explicit Schema {#with-explicit-schema}
 
 ``` sql
-CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
+CREATE [OR REPLACE] TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
 (
     name1 [type1] [NULL|NOT NULL] [DEFAULT|MATERIALIZED|ALIAS expr1] [compression_codec] [TTL expr1],
     name2 [type2] [NULL|NOT NULL] [DEFAULT|MATERIALIZED|ALIAS expr2] [compression_codec] [TTL expr2],
@@ -34,21 +34,21 @@ If necessary, primary key can be specified, with one or more key expressions.
 ### With a Schema Similar to Other Table {#with-a-schema-similar-to-other-table}
 
 ``` sql
-CREATE TABLE [IF NOT EXISTS] [db.]table_name AS [db2.]name2 [ENGINE = engine]
+CREATE [OR REPLACE]  TABLE [IF NOT EXISTS] [db.]table_name AS [db2.]name2 [ENGINE = engine]
 ```
 
 Creates a table with the same structure as another table. You can specify a different engine for the table. If the engine is not specified, the same engine will be used as for the `db2.name2` table.
 
-## From a Table Function {#from-a-table-function}
+### From a Table Function {#from-a-table-function}
 
 ``` sql
-CREATE TABLE [IF NOT EXISTS] [db.]table_name AS table_function()
+CREATE [OR REPLACE] TABLE [IF NOT EXISTS] [db.]table_name AS table_function()
 ```
 
 Creates a table with the structure and data returned by a [table function](../../../sql-reference/table-functions/index.md#table-functions).
 
 ``` sql
-CREATE TABLE [IF NOT EXISTS] [db.]table_name ENGINE = engine AS SELECT ...
+CREATE [OR REPLACE] TABLE [IF NOT EXISTS] [db.]table_name ENGINE = engine AS SELECT ...
 ```
 
 Creates a table with a structure like the result of the `SELECT` query, with the `engine` engine, and fills it with data from SELECT.
@@ -259,3 +259,68 @@ CREATE TEMPORARY TABLE [IF NOT EXISTS] table_name
 In most cases, temporary tables are not created manually, but when using external data for a query, or for distributed `(GLOBAL) IN`. For more information, see the appropriate sections
 
 It’s possible to use tables with [ENGINE = Memory](../../../engines/table-engines/special/memory.md) instead of temporary tables.
+
+## REPLACE TABLE {#replace-table-query}
+
+`REPLACE` query allows you to add, drop, and rename data in the tables.
+
+!!!note "Note"
+    This query is supported only for [Atomic](../../../engines/database_engines/atomic.md) database engine.
+
+If you need to reject(delete) some data from a table, you can create a new table and fill it with a `SELECT` statement that doesn't retrieve unwanted data, then rename it to old table name:
+
+```sql
+CREATE TABLE myNewTable AS myOldTable;
+```
+
+Then load data with:
+
+```sql
+INSERT INTO myNewTable SELECT * FROM myOldTable WHERE CounterID <12345;
+```
+
+Drop old table and rename:
+
+```sql
+DROP TABLE myOldTable;
+RENAME TABLE myNewTable TO myOldTable;
+```
+
+Instead of above, you can use the following:
+
+```sql
+REPLACE TABLE myOldTable SELECT * FROM myOldTable WHERE CounterID <12345;
+```
+
+**Examples:**
+
+`REPLACE` for a non-existent table will cause an error.
+
+```sql
+CREATE DATABASE base ENGINE = Atomic;
+REPLACE TABLE base.t1 (n UInt64, s String) ENGINE = MergeTree ORDER BY n; -- { serverError 60 }
+```
+
+Using `REPLACE` query to change data in columns.
+
+```sql
+CREATE OR REPLACE TABLE base.t1 (n UInt64, s String) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (1, 'test');
+SELECT * FROM base.t1;
+
+CREATE OR REPLACE TABLE base.t1 (n UInt64, s Nullable(String)) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (2, null);
+SELECT * FROM base.t1;
+
+REPLACE TABLE base.t1 (n UInt64) ENGINE = MergeTree ORDER BY n;
+INSERT INTO base.t1 VALUES (3);
+SELECT * FROM base.t1;
+```
+
+```text
+1   test
+2   \N
+3
+```
+
+ [Original article](https://clickhouse.tech/docs/en/sql-reference/statements/create/table) <!--hide-->