SQLite REGEXP

SQLite’s REGEXP operator is a powerful tool for working with regular expressions in SQL statements. Regular expressions are patterns used to match text and are widely used in programming and data processing.

The REGEXP operator in SQLite allows you to use regular expressions in your SQL queries to search for specific patterns within text fields. The operator is used in a WHERE clause, along with the LIKE operator, to match patterns within a text column.

Syntax

The syntax of the REGEXP operator is as follows:

column_name REGEXP pattern

Here, column_name is the name of the column you want to search, and pattern is the regular expression pattern you want to match against.

Example

For example, let’s say you have a table of names and you want to search for all the names that start with the letter “J”. You can use the following SQL statement:

SELECT * 
FROM names 
WHERE name REGEXP '^J';

In this example, the regular expression ^J matches any name that starts with the letter “J”. The ^ character is used to anchor the pattern to the beginning of the string.

Similarly, you can use regular expressions to search for patterns within text strings, such as email addresses, phone numbers, or postal codes. The REGEXP operator supports a wide range of regular expression patterns, including character classes, quantifiers, alternation, and grouping.

How to use REGEXP

Find all rows in a table where a certain column contains the word “apple” followed by any three letters:

SELECT * 
FROM mytable 
WHERE mycolumn REGEXP 'apple...';

Find all rows where a certain column contains only uppercase letters:

SELECT * 
FROM mytable 
WHERE mycolumn REGEXP '^[A-Z]+$';

Find all rows where a certain column contains a string that starts with “http” or “https”:

SELECT * 
FROM mytable 
WHERE mycolumn REGEXP '^(http|https):\/\/';

Find all rows where a certain column contains a string that ends with “.com”:

SELECT * 
FROM mytable 
WHERE mycolumn REGEXP '\.com$';

Find all rows where a certain column contains a string that starts with a digit and ends with a letter:

SELECT * 
FROM mytable 
WHERE mycolumn REGEXP '^[0-9].*[a-zA-Z]$';

It’s worth noting that the REGEXP operator is case-sensitive by default. However, you can use the REGEXP nocase modifier to perform a case-insensitive search.

In summary, the REGEXP operator in SQLite provides a powerful and flexible way to search for patterns within text fields. Whether you’re working with names, addresses, or any other type of textual data, regular expressions can help you extract meaningful information and gain valuable insights from your data.