This article explains how to restore an SQLite database from within the SQLite command line interface.
There are a few ways to restore a database from the SQLite CLI.
One way to do it is to simply attach a new database using the backup file (or a copy of it). Another way to restore a database is to use the .restore dot command to restore the database file to your chosen database within SQLite CLI.
SQLite has a group_concat() function that allows you to concatenate multiple results returned for a column into one.
This is sometimes referred to as “string aggregation”.
For example, when querying a database, instead of having each column’s value output in a new row, you can use group_concat() to have them output as a comma separated list.
The SQLite substr() function allows you to return a substring from a string, based on a given starting location within the string.
It requires two arguments, and accepts a third optional argument.
Continue readingIn SQLite, the round() function allows you to round numbers up or down to a given decimal place.
It returns a floating-point value from the first argument, with the number of decimal places that you specify in the (optional) second argument.
If you don’t provide the second argument, it’s assumed to be 0.
Continue readingThe SQLite lower() function allows you to convert a string to lowercase characters.
More precisely, it returns a copy of its argument, with all ASCII characters converted to lowercase.
Continue readingThe SQLite upper() function allows you to convert a string to uppercase characters.
More precisely, it returns a copy of its argument, with all ASCII characters converted to uppercase.
Continue readingThe SQLite nullif() function is a handy function that allows you to treat certain values as NULL when required.
It’s not to be confused with the ifnull() function, which does the opposite – enables you to treat NULL values as something else.
The nullif() function accepts two arguments, and returns its first argument if the arguments are different and NULL if the arguments are the same.
The SQLite random() function returns a pseudo-random integer between -9223372036854775808 and +9223372036854775807.
A pseudo-random number is a number that appears to be random, but is not truely random. A pseudo-random number is not truely random because its value was generated by a known seed. However, a pseudo-random number will appear to be random if the user has no knowledge of the seed or algorithm that created it.
Therefore, pseudo-random numbers are often considered good enough for many applications.
Continue readingThe SQLite ifnull() function allows you to replace NULL values with another value.
It takes two arguments, and it returns a copy of its first non-NULL argument, or NULL if both arguments are NULL.
The ifnull() function is equivalent to coalesce() with two arguments.
In SQLite, the coalesce() function returns a copy of its first non-NULL argument, or NULL if all arguments are NULL.
It’s similar to the ifnull() function, except that coalesce() accepts more than two arguments (ifnull() only accepts two arguments).