Beyond Exact Matches: Wildcard Techniques for Multi-Word Search in PostgreSQL

Here's how you can achieve "wildcard LIKE for any of a list of words" in PostgreSQL for your specific case of finding rows containing "sql" or "postgresql":

Using ANY with LIKE:

This approach utilizes the ANY operator along with LIKE. Here's the breakdown:

• We define an array containing the wildcard patterns for each word you want to match ('sql%', '%postgresql%'). The % wildcard represents zero or more characters.
• The ANY operator checks if the value in your search column (your_column) matches any of the patterns in the array.

Here's the query:

SELECT *
FROM your_table
WHERE your_column LIKE ANY (array['%sql%', '%postgresql%']);

Using SIMILAR TO:

PostgreSQL also provides the SIMILAR TO operator (equivalent to ~~), which is similar to LIKE but offers some additional features like supporting alternations (OR conditions).

Here's the query using SIMILAR TO:

SELECT *
FROM your_table
WHERE your_column SIMILAR TO ANY (array['%sql%', '%postgresql%']);

Both methods will return rows where the your_column contains either "sql" or "postgresql" (or any combination of characters with "sql" or "postgresql" within them).

Important Note:

While these methods work, for simple string matching against a fixed list of words, using a series of OR conditions might be more efficient:

SELECT *
FROM your_table
WHERE your_column LIKE '%sql%' OR your_column LIKE '%postgresql%';

Using ANY with LIKE:

SELECT *
FROM your_table  -- Replace with your table name
WHERE your_column LIKE ANY (array['%sql%', '%postgresql%']);  -- Replace 'your_column' with your actual column name

This query searches your table (your_table) for rows where the value in your_column matches any of the patterns: "sql" or "postgresql" (or any combination of characters containing them).

Using SIMILAR TO:

SELECT *
FROM your_table  -- Replace with your table name
WHERE your_column SIMILAR TO ANY (array['%sql%', '%postgresql%']);  -- Replace 'your_column' with your actual column name

This query achieves the same result using the SIMILAR TO operator.

OR conditions:

This approach is particularly efficient for a small, fixed list of words:

SELECT *
FROM your_table
WHERE your_column LIKE '%sql%' OR your_column LIKE '%postgresql%';

This query explicitly checks if the value in your_column matches "sql" OR "postgresql".

Regular Expressions:

For more complex matching patterns, you can leverage regular expressions with the ~ (LIKE) or ~* (ILIKE - case-insensitive) operators. However, regular expressions can be less intuitive for beginners.

Here's an example using a regular expression to match "sql" or "postgresql" (ignoring case):

SELECT *
FROM your_table
WHERE your_column ~* '^(sql|postgresql)$';

This regular expression ensures the entire value in your_column matches either "sql" or "postgresql" (case-insensitive).

pg_trgm extension (PostgreSQL 9.6+):

PostgreSQL offers the pg_trgm extension that provides text similarity operators like % (similarity) and <@ (word similarity). These operators can be helpful for fuzzy matching based on word proximity or stemming (reducing words to their root form).

Here's an example using % for basic similarity search (might find rows containing "mysqldatabase" or "SQLtutorial"):

SELECT *
FROM your_table
WHERE your_column % 'sql | postgresql';

Choosing the Right Method:

• For a small, fixed list of words, OR conditions offer good performance and readability.
• For complex matching patterns, regular expressions provide flexibility but require more expertise.
• For fuzzy matching or stemming, consider pg_trgm (if applicable).