ClickHouse/docs/zh/sql-reference/statements/alter/setting.md

---
sidebar_position: 38
sidebar_label: SETTING
---

# 表设置操作 {#table_settings_manipulations}

这是一组更改表设置的操作。你可以修改设置或将其重置为默认值。单个查询可以同时更改多个设置。 如果指定名称的设置不存在，则查询会引发异常。

**语法**

``` sql
ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY|RESET SETTING ...
```

!!! note "注意"
    这些查询只能应用于 [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) 表。


## 修改设置 {#alter_modify_setting}

更改表设置

**语法**

```sql
MODIFY SETTING setting_name=value [, ...]
```

**示例**

```sql
CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id;
ALTER TABLE example_table MODIFY SETTING max_part_loading_threads=8, max_parts_in_total=50000;
```

## 重置设置 {#alter_reset_setting}

重置表设置为默认值。如果设置处于默认状态，则不采取任何操作。

**语法**

```sql
RESET SETTING setting_name [, ...]
```

**示例**

```sql
CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id
    SETTINGS max_part_loading_threads=8;
ALTER TABLE example_table RESET SETTING max_part_loading_threads;
```

**参见**

-   [MergeTree settings](../../../operations/settings/merge-tree-settings.md)