SQL Comments.

Comments Are An Important Part Of Sql Programming, As They Help To Explain The Purpose And Function Of Code, And Make It Easier To Read And Understand. There Are Two Types Of Comments In Sql: Single-line Comments And Multi-line Comments.

Single-line Comments Start With Two Hyphens (--), And Continue Until The End Of The Line. Here's An Example Of A Single-line Comment In Sql:

```

SELECT * FROM customers -- This selects all records from the customers table

WHERE country = 'USA';

```

In The Above Example, The Comment Starts With "--" And Continues Until The End Of The Line. This Comment Is Used To Explain What The Sql Statement Is Doing.

Multi-line Comments Start With "/*" And End With "*/". They Can Span Multiple Lines, And Are Used To Provide More Detailed Explanations Of Sql Statements. Here's An Example Of A Multi-line Comment In Sql:

```

/* This SQL statement selects all records from the customers table

where the country is 'USA' and the state is 'California'. */

SELECT * FROM customers

WHERE country = 'USA'

AND state = 'California';

```

In The Above Example, The Multi-line Comment Starts With "/*" And Ends With "*/". The Comment Spans Multiple Lines, And Provides A Detailed Explanation Of What The Sql Statement Is Doing.

Both Single-line And Multi-line Comments Are Useful In Sql Programming, And Can Help To Make Code Easier To Read And Understand. They Can Also Be Used To Temporarily Disable Sections Of Sql Code During Development And Testing, Without Having To Delete The Code Entirely.