# SQL Comments

### SQL Comments

Comments are used to explain sections of SQL statements, or to prevent execution of SQL statements.

> **Note: The examples in this chapter will not work in Firefox and Microsoft Edge!**
>
> Comments are not supported in Microsoft Access databases. Firefox and Microsoft Edge are using Microsoft Access database in our examples.\
>

**Single Line Comments**

Single line comments start with --.

Any text between -- and the end of the line will be ignored (will not be executed).

The following example uses a single-line comment as an explanation:

```sql
--Select all:
SELECT * FROM Customers;
```

The following example uses a single-line comment to ignore the end of a line:

```sql
SELECT * FROM Customers -- WHERE City='Berlin';
```

The following example uses a single-line comment to ignore a statement:

```sql
SELECT * FROM Customers -- WHERE City='Berlin';
```

The following example uses a single-line comment to ignore a statement:

```sql
--SELECT * FROM Customers;
SELECT * FROM Products;
```

### Multi-line Comments

Multi-line comments start with /\* and end with \*/.

Any text between /\* and \*/ will be ignored.

The following example uses a multi-line comment as an explanation:

```sql
/*Select all the columns
of all the records
in the Customers table:*/
SELECT * FROM Customers;
```

The following example uses a multi-line comment to ignore many statements:

```sql
/*SELECT * FROM Customers;
SELECT * FROM Products;
SELECT * FROM Orders;
SELECT * FROM Categories;*/
SELECT * FROM Suppliers;
```

To ignore just a part of a statement, also use the /\* \*/ comment.

The following example uses a comment to ignore part of a line:

```sql
SELECT CustomerName, /*City,*/ Country FROM Customers;
```

The following example uses a comment to ignore part of a statement:

```sql
SELECT * FROM Customers WHERE (CustomerName LIKE 'L%'
OR CustomerName LIKE 'R%' /*OR CustomerName LIKE 'S%'
OR CustomerName LIKE 'T%'*/ OR CustomerName LIKE 'W%')
AND Country='USA'
ORDER BY CustomerName;
```

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