In PostgreSQL, you can use the OVERLAPS operator to test for overlapping time periods.
The function returns true when two time periods (defined by their endpoints) overlap, and false when they do not overlap.
In PostgreSQL, you can use the OVERLAPS operator to test for overlapping time periods.
The function returns true when two time periods (defined by their endpoints) overlap, and false when they do not overlap.
SQLite doesn’t have a concat() function like many other database management systems, such as SQL Server’s concat() and MySQL’s concat().
However, that doesn’t mean you can’t concatenate two strings in SQLite.
SQLite has a concatenation operator (||) that you can use to concatenate two strings.
In SQLite, you can use the LIKE operator in your queries to do a pattern matching comparison.
For example, you can add it to your WHERE clause in order to return only rows that match a given pattern.
However, adding it to the WHERE clause isn’t the only way you can use the LIKE operator. You can also use it to return a boolean value.
MySQL has a number of functions and operators that allow us to perform operations using regular expressions (regex). This article presents two operators and one function that enable us to find out if a string matches a regular expression specified by a given pattern.
These regex functions and operators are:
These are all basically equivalent, as the operators (the second two) are both synonyms of the function (the first one). In any case, you can see examples of all three in action below.
In MySQL, the MATCH() function performs a full-text search. It accepts a comma separated list of table columns to be searched.
The table/s must have a FULLTEXT index before you can do a full-text search against them (although boolean queries against a MyISAM search index can work — albeit slowly — even without a FULLTEXT index).
You can create a FULLTEXT index when creating the table (using the CREATE TABLE statement), or you can use the ALTER TABLE statement or the CREATE INDEX statement if the table already exists.
By default, the search is case-insensitive. To perform a case-sensitive search, use a case-sensitive or binary collation for the indexed columns.
In MySQL, you can use NOT LIKE to perform a negation of the LIKE operator. In other words, NOT LIKE returns the opposite result to LIKE.
If the string matches the pattern provided, the result is 0, otherwise it’s 1.
The pattern doesn’t necessarily need to be a literal string. This function can be used with string expressions and table columns.