What are the functions for splicing fields in SQL?

SQL provides a variety of functions for splicing fields, including CONCAT(), || operator and FORMAT(). The CONCAT() function concatenates multiple strings, the || operator does the same thing, and the FORMAT() function can be used to convert values ​​into a specific format and concatenate strings. These functions are useful for combining fields to create new fields or copying data.

Function to splice fields in SQL

In SQL, you can use several functions to splice fields. These functions are useful for combining multiple fields to create new fields or copying data from one field to another.

CONCAT() function

CONCAT() function is the most commonly used splicing function. It concatenates two or more strings together and returns a new string. The syntax is as follows:

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

For example:

<code class="sql">SELECT CONCAT(first_name, ' ', last_name) AS full_name
FROM employees;</code>

This query splices the first_name and last_name fields in the employees table together to create the full_name field.

Other splicing functions

In addition to the CONCAT() function, there are several other functions that can be used to splice fields:

• || Operator: || operator can also be used to concatenate strings. It has the same functionality as the CONCAT() function but with simpler syntax. For example:

<code class="sql">SELECT first_name || ' ' || last_name AS full_name
FROM employees;</code>

• FORMAT() function: The FORMAT() function can be used to convert a value into a string in a specific format. It can also be used to concatenate strings. For example:

<code class="sql">SELECT FORMAT(salary, '$#,##0.00') || ' per year' AS salary_formatted
FROM employees;</code>

This query converts the salary field to a currency-formatted string and appends the text "per year".

Usage Notes

When using the splice function, you need to pay attention to the following:

• If any input string is NULL, then The result will also be NULL.
• When using the || operator, if any input string is an empty string, the result will also be an empty string.
• The CONCAT() function and FORMAT() function can handle text, numbers, and other data types.
• When splicing multiple fields, you can add delimiters (such as spaces or commas) to enhance readability.

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