SQL IN 操作符

IN 操作符允许您在 WHERE 子句中规定多个值。

## 语法

### SQL IN 语法

```sql
SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1,value2,...);
```

### SQL IN SELECT语法

```sql
SELECT column_name(s)
FROM table_name
WHERE column_name IN (select column from table_w3c where ...);
```

## 实例

### 演示数据库

在本教程中，我们将使用众所周知的 Northwind 样本数据库。

下面是选自 "Customers" 表的数据：

| CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
| 4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
| 5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |

下面的 SQL 语句选取 City 为 "Paris" 或 "London" 的所有客户：

```sql
SELECT * FROM Customers
WHERE City IN ('Paris','London');
```