How to splice in sql

A variety of methods can be used for string concatenation in SQL, including using the concatenation operator ( ), CONCAT function, || operator (Oracle and MySQL), FORMAT function (SQL Server) and STUFF function (SQL Server). The specific choice depends on the complexity of the splicing operation and the database system used.

String splicing method in SQL

In SQL, string splicing is a method of combining multiple characters The process of combining strings into a single string. There are several ways to implement string concatenation, depending on the database system used.

1. Use the concatenation operator ( )

The easiest way is to use the concatenation operator ( ) to concatenate multiple strings. For example:

<code class="sql">SELECT 'Hello' + ' ' + 'World'; -- 输出：Hello World</code>

2. Use the CONCAT function

The CONCAT function is specially used for string concatenation. The syntax is:

<code class="sql">CONCAT(string1, string2, ..., stringN)</code>

For example:

<code class="sql">SELECT CONCAT('Hello', ' ', 'World'); -- 输出：Hello World</code>

3. Use the || operator (Oracle and MySQL)

In Oracle and MySQL, You can also use the || operator for string concatenation. Its syntax is similar to the operator:

<code class="sql">SELECT 'Hello' || ' ' || 'World'; -- 输出：Hello World (Oracle 和 MySQL)</code>

4. Using the FORMAT function (SQL Server)

In SQL Server, you can use the FORMAT function for string concatenation. The syntax is:

<code class="sql">FORMAT(string, argument1, ..., argumentN)</code>

For example:

<code class="sql">SELECT FORMAT('Hello {0} World', 'there'); -- 输出：Hello there World (SQL Server)</code>

5. Using the STUFF function (SQL Server)

The STUFF function can be used to insert in a string Or replace substring. You can also use it to implement string concatenation. The syntax is:

<code class="sql">STUFF(string, start, length, insert_string)</code>

For example:

<code class="sql">SELECT STUFF('Hello ', LEN('Hello ') + 1, 0, 'World'); -- 输出：Hello World (SQL Server)</code>

Choose the appropriate method

Which string splicing method to choose depends on the specific situation. For simple concatenation, the operator or the CONCAT function are usually good choices. If more complex splicing operations are required, you can use the STUFF function or the FORMAT function.

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