What is used to express a certain character contained in Oracle?

The representation method of containing a certain character in Oracle is: using the wildcard character %, which means matching any number of any characters. Usage: SELECT * FROM table_name WHERE column_name LIKE '%character%'. In addition, Oracle also provides other wildcards: _ matches a single character; [] matches a single character within square brackets; [^] matches a single character outside square brackets.

The representation method containing a certain character in Oracle

In Oracle, the representation method containing a certain character can be used Wildcard character%.%means match any number of any characters (including zero).

Usage

To find a string containing specific characters, use the following syntax:

SELECT * FROM table_name WHERE column_name LIKE '%character%';

Where:

• table_nameis the name of the table you want to search for.
• column_nameis the column name you want to search for.
• characteris the character you are looking for.

Example

To find all names that contain the letter "a", you can use the following query:

SELECT * FROM employee WHERE name LIKE '%a%';

Other wildcard characters

In addition to%, Oracle also provides other wildcard characters for pattern matching:

• _(underscore) : Matches any single character.
• [](square brackets): Matches any single character specified within square brackets.
• [^](negative square brackets): Matches any single character not specified within the square brackets.

Tip

• %is a wildcard, so use it with caution to avoid unexpected results.
• If you want to find a specific sequence of characters, you can use_instead of%.
• You can use the escape character\in a wildcard to find special characters (such as%or_).

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