DOCSUP-4194: Updated CREATE TABLE statement with PRIMARY KEY section (#17213)

* Section added

* Syntax corrected

Co-authored-by: Olga Revyakina <revolg@yandex-team.ru>

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

@@ -29,6 +29,8 @@ A column description is `name type` in the simplest case. Example: `RegionID UIn
 
 Expressions can also be defined for default values (see below).
 
+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
@@ -97,6 +99,34 @@ If you add a new column to a table but later change its default expression, the
 
 It is not possible to set default values for elements in nested data structures.
 
+## Primary Key {#primary-key}
+
+You can define a [primary key](../../../engines/table-engines/mergetree-family/mergetree.md#primary-keys-and-indexes-in-queries) when creating a table. Primary key can be specified in two ways: 
+
+- inside the column list
+
+``` sql
+CREATE TABLE db.table_name 
+( 
+    name1 type1, name2 type2, ..., 
+    PRIMARY KEY(expr1[, expr2,...])]
+) 
+ENGINE = engine;
+```
+
+- outside the column list
+
+``` sql
+CREATE TABLE db.table_name
+( 
+    name1 type1, name2 type2, ...
+) 
+ENGINE = engine
+PRIMARY KEY(expr1[, expr2,...]);
+```
+
+You can't combine both ways in one query.
+
 ## Constraints {#constraints}
 
 Along with columns descriptions constraints could be defined: