Oracle TO_CLOB(character) Function

Oracle TO_CLOB(character) is a built-in function that is used to convert NCLOB values or other character strings in LOB columns to CLOB values.

Oracle `TO_CLOB(character)` Syntax

Here is the syntax for the Oracle TO_CLOB(character) function:

TO_CLOB(lob_column | char)

Parameters

lob_column | char: Required. The data to be converted. char can be any data type, including CHAR, VARCHAR2, NCHAR, NVARCHAR2, CLOB, or NCLOB.

Return Value

The Oracle TO_CLOB(character) function is used to convert NCLOB values or other character strings in LOB columns to CLOB values.

If any of the parameters is NULL, TO_CLOB(character) will return NULL.

Oracle `TO_CLOB(character)` Examples

Here are a few examples that demonstrate the usage of the Oracle TO_CLOB(character) function.

Basic Usage

The following statement converts NCLOB data from the sample pm.print_media table to CLOB and inserts it into the CLOB column, replacing the existing data in that column.

UPDATE print_media
   SET ad_finaltext = TO_CLOB(ad_fltextn);

NULL Parameters

If any of the parameters is NULL, TO_CLOB() will return NULL.

SET NULL 'NULL';
SELECT
  TO_CLOB(NULL)
FROM dual;

输出：

TO_CLOB(NULL)
________________
NULL

In this example, we use the statement SET NULL 'NULL'; to display the NULL value as the string 'NULL'.

Conclusion