Concat usage in oracle

The CONCAT function in Oracle is used to concatenate multiple strings into one. The usage is CONCAT(string1, string2, ...). The input is multiple strings and the output is the new string after concatenation. It supports NULL value handling and automatic string conversion to insert text using delimiters. However, it is recommended to use the DBMS_LOB.APPEND or STRINGAGG function to optimize performance when connecting to a large number of connections.

CONCAT function in Oracle

Question:What is the CONCAT function in Oracle? use?

Answer: The CONCAT function is used to concatenate two or more strings together to form a new string.

Usage:

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

Parameters:

• string1, string2,..., stringN: To connect String.

Example:

<code class="sql">SELECT CONCAT('Hello', ' ', 'World') FROM dual;

-- 输出：Hello World</code>

Other functions:

NULL value processing:If If any input string is NULL, the output string is also NULL.

Automatic conversion to string: The CONCAT function automatically converts any non-string input value to a string.

Delimiter: Use the optional delimiter parameter to insert text between concatenated strings.

<code class="sql">SELECT CONCAT('Hello', ' ', 'World', '!') FROM dual;

-- 输出：Hello World!</code>

Performance Note: The CONCAT function may impact performance because it requires assembling new strings at runtime. For large numbers of connections, it is recommended to use the DBMS_LOB.APPEND or STRINGAGG function.

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