Beyond Exact Matches: Wildcard Techniques for Multi-Word Search in 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%';
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).
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 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).
sql postgresql