Merge pull request #48576 from ClickHouse/evillique-patch-1

Update syntax.md

docs/en/sql-reference/syntax.md

@@ -14,7 +14,7 @@ The `INSERT` query uses both parsers:
 INSERT INTO t VALUES (1, 'Hello, world'), (2, 'abc'), (3, 'def')
 ```
 
-The `INSERT INTO t VALUES` fragment is parsed by the full parser, and the data `(1, 'Hello, world'), (2, 'abc'), (3, 'def')` is parsed by the fast stream parser. You can also turn on the full parser for the data by using the [input_format_values_interpret_expressions](../operations/settings/settings-formats.md#settings-input_format_values_interpret_expressions) setting. When `input_format_values_interpret_expressions = 1`, ClickHouse first tries to parse values with the fast stream parser. If it fails, ClickHouse tries to use the full parser for the data, treating it like an SQL [expression](#syntax-expressions).
+The `INSERT INTO t VALUES` fragment is parsed by the full parser, and the data `(1, 'Hello, world'), (2, 'abc'), (3, 'def')` is parsed by the fast stream parser. You can also turn on the full parser for the data by using the [input_format_values_interpret_expressions](../operations/settings/settings-formats.md#input_format_values_interpret_expressions) setting. When `input_format_values_interpret_expressions = 1`, ClickHouse first tries to parse values with the fast stream parser. If it fails, ClickHouse tries to use the full parser for the data, treating it like an SQL [expression](#expressions).
 
 Data can have any format. When a query is received, the server calculates no more than [max_query_size](../operations/settings/settings.md#settings-max_query_size) bytes of the request in RAM (by default, 1 MB), and the rest is stream parsed.
 It allows for avoiding issues with large `INSERT` queries.
@@ -45,7 +45,7 @@ You can check whether a data type name is case-sensitive in the [system.data_typ
 
 In contrast to standard SQL, all other keywords (including functions names) are **case-sensitive**.
 
-Keywords are not reserved; they are treated as such only in the corresponding context. If you use [identifiers](#syntax-identifiers) with the same name as the keywords, enclose them into double-quotes or backticks. For example, the query `SELECT "FROM" FROM table_name` is valid if the table `table_name` has column with the name `"FROM"`.
+Keywords are not reserved; they are treated as such only in the corresponding context. If you use [identifiers](#identifiers) with the same name as the keywords, enclose them into double-quotes or backticks. For example, the query `SELECT "FROM" FROM table_name` is valid if the table `table_name` has column with the name `"FROM"`.
 
 ## Identifiers
 
@@ -54,7 +54,7 @@ Identifiers are:
 -   Cluster, database, table, partition, and column names.
 -   Functions.
 -   Data types.
--   [Expression aliases](#syntax-expression_aliases).
+-   [Expression aliases](#expression_aliases).
 
 Identifiers can be quoted or non-quoted. The latter is preferred.
 
@@ -108,7 +108,7 @@ Depending on the data format (input or output), `NULL` may have a different repr
 
 There are many nuances to processing `NULL`. For example, if at least one of the arguments of a comparison operation is `NULL`, the result of this operation is also `NULL`. The same is true for multiplication, addition, and other operations. For more information, read the documentation for each operation.
 
-In queries, you can check `NULL` using the [IS NULL](../sql-reference/operators/index.md#operator-is-null) and [IS NOT NULL](../sql-reference/operators/index.md) operators and the related functions `isNull` and `isNotNull`.
+In queries, you can check `NULL` using the [IS NULL](../sql-reference/operators/index.md#is-null) and [IS NOT NULL](../sql-reference/operators/index.md#is-not-null) operators and the related functions `isNull` and `isNotNull`.
 
 ### Heredoc
 
@@ -149,7 +149,7 @@ For example, the following SQL defines parameters named `a`, `b`, `c` and `d` -
 SET param_a = 13;
 SET param_b = 'str';
 SET param_c = '2022-08-04 18:30:53';
-SET param_d = {'10': [11, 12], '13': [14, 15]}';
+SET param_d = {'10': [11, 12], '13': [14, 15]};
 
 SELECT
    {a: UInt32},
@@ -166,7 +166,7 @@ Result:
 
 If you are using `clickhouse-client`, the parameters are specified as `--param_name=value`. For example, the following parameter has the name `message` and it is retrieved as a `String`:
 
-```sql
+```bash
 clickhouse-client --param_message='hello' --query="SELECT {message: String}"
 ```
 
@@ -190,7 +190,7 @@ Query parameters are not general text substitutions which can be used in arbitra
 ## Functions
 
 Function calls are written like an identifier with a list of arguments (possibly empty) in round brackets. In contrast to standard SQL, the brackets are required, even for an empty argument list. Example: `now()`.
-There are regular and aggregate functions (see the section “Aggregate functions”). Some aggregate functions can contain two lists of arguments in brackets. Example: `quantile (0.9) (x)`. These aggregate functions are called “parametric” functions, and the arguments in the first list are called “parameters”. The syntax of aggregate functions without parameters is the same as for regular functions.
+There are regular and aggregate functions (see the section [Aggregate functions](/docs/en/sql-reference/aggregate-functions/index.md)). Some aggregate functions can contain two lists of arguments in brackets. Example: `quantile (0.9) (x)`. These aggregate functions are called “parametric” functions, and the arguments in the first list are called “parameters”. The syntax of aggregate functions without parameters is the same as for regular functions.
 
 ## Operators
 
@@ -199,7 +199,7 @@ For example, the expression `1 + 2 * 3 + 4` is transformed to `plus(plus(1, mult
 
 ## Data Types and Database Table Engines
 
-Data types and table engines in the `CREATE` query are written the same way as identifiers or functions. In other words, they may or may not contain an argument list in brackets. For more information, see the sections “Data types,” “Table engines,” and “CREATE”.
+Data types and table engines in the `CREATE` query are written the same way as identifiers or functions. In other words, they may or may not contain an argument list in brackets. For more information, see the sections [Data types](/docs/en/sql-reference/data-types/index.md), [Table engines](/docs/en/engines/table-engines/index.md), and [CREATE](/docs/en/sql-reference/statements/create/index.md).
 
 ## Expression Aliases
 
@@ -211,17 +211,17 @@ expr AS alias
 
 -   `AS` — The keyword for defining aliases. You can define the alias for a table name or a column name in a `SELECT` clause without using the `AS` keyword.
 
-        For example, `SELECT table_name_alias.column_name FROM table_name table_name_alias`.
+    For example, `SELECT table_name_alias.column_name FROM table_name table_name_alias`.
 
-        In the [CAST](./functions/type-conversion-functions.md#type_conversion_function-cast) function, the `AS` keyword has another meaning. See the description of the function.
+    In the [CAST](./functions/type-conversion-functions.md#castx-t) function, the `AS` keyword has another meaning. See the description of the function.
 
 -   `expr` — Any expression supported by ClickHouse.
 
-        For example, `SELECT column_name * 2 AS double FROM some_table`.
+    For example, `SELECT column_name * 2 AS double FROM some_table`.
 
--   `alias` — Name for `expr`. Aliases should comply with the [identifiers](#syntax-identifiers) syntax.
+-   `alias` — Name for `expr`. Aliases should comply with the [identifiers](#identifiers) syntax.
 
-        For example, `SELECT "table t".column_name FROM table_name AS "table t"`.
+    For example, `SELECT "table t".column_name FROM table_name AS "table t"`.
 
 ### Notes on Usage
 
@@ -254,11 +254,11 @@ Received exception from server (version 18.14.17):
 Code: 184. DB::Exception: Received from localhost:9000, 127.0.0.1. DB::Exception: Aggregate function sum(b) is found inside another aggregate function in query.
 ```
 
-In this example, we declared table `t` with column `b`. Then, when selecting data, we defined the `sum(b) AS b` alias. As aliases are global, ClickHouse substituted the literal `b` in the expression `argMax(a, b)` with the expression `sum(b)`. This substitution caused the exception. You can change this default behavior by setting [prefer_column_name_to_alias](../operations/settings/settings.md#prefer_column_name_to_alias) to `1`.
+In this example, we declared table `t` with column `b`. Then, when selecting data, we defined the `sum(b) AS b` alias. As aliases are global, ClickHouse substituted the literal `b` in the expression `argMax(a, b)` with the expression `sum(b)`. This substitution caused the exception. You can change this default behavior by setting [prefer_column_name_to_alias](../operations/settings/settings.md#prefer-column-name-to-alias) to `1`.
 
 ## Asterisk
 
-In a `SELECT` query, an asterisk can replace the expression. For more information, see the section “SELECT”.
+In a `SELECT` query, an asterisk can replace the expression. For more information, see the section [SELECT](/docs/en/sql-reference/statements/select/index.md#asterisk).
 
 ## Expressions