If you need to add a “count” column to the result set of a database query when using SQLite, you can use the count() function to provide the count, and the GROUP BY clause to specify the column for which to group the results.
Tag: how to
How SQLite Count() Works
The SQLite count() function can be used to return the number of rows in a result set.
It can also be used to return the number of times a given column is not NULL in the result set.
It can be used in two ways. If you pass in the asterisk (*) wildcard character, it will return the total number of rows in the group. If you provide the name of a column, it will return the number of times that column is not NULL.
SQLite Date & Time Functions
SQLite supports five functions for working with dates and times. These are:
All of these functions accept a time string as an argument. They also accept other arguments for modifying/formatting the output.
The strftime() function is the most versatile function of the five. In fact, this function can do everything the other four can.
In other words, you could use strftime() for all your date and time formatting requirements. The other four functions are available solely for convenience.
3 Ways to Generate a CREATE TABLE Script from an Existing Table in SQLite
This article contains three ways to generate an SQL script from an existing table in SQLite.
All three methods generate the CREATE TABLE script, but the last method also generates the INSERT statements for inserting the data.
Return a List of Databases in SQLite
When using the SQLite command line interface, you can use the .databases command to return a list of attached databases. More specifically, it returns the names and file names/location of each attached database.
You can also use the PRAGMA database_list statement to return a list of databases attached to the current database connection.
Include Column Names in SQLite Query Results
By default, the SQLite command line interface displays query results using a pipe-separated list, without column headers.
This might be fine if you’re using the results in an application that doesn’t need the column names, but if you’re just a human, it can make it hard to read the data, especially if there are lots of columns.
Fortunately, there’s a quick way to present the column names in your query results.
Actually, there are at least a couple of ways to do this, and I explain them in this article.
Continue readingBackup an SQLite Database
The SQLite command line shell provides the .backup dot command that enables you to quickly and easily back up a database.
To use this command, provide the name of the database you want to back up, and a file name for the backup file.
Continue readingClone an SQLite Database
You can use the SQLite .clone dot command to create a clone of the current database.
The way it works is quite simple. You simply use .clone newdb where newdb is the name of the new database you want created.
Export an Entire SQLite Database to an SQL File
The SQLite command line provides several methods for exporting or backing up an entire database. One of those involves the .dump dot command.
The .dump command enables you to convert a whole database to a single ASCII text file. In other words, it renders the whole database as SQL. The text file contains all the SQL statements required to create the tables, insert data, etc.
You can also use .dump to create a compressed file. I outline both of these methods below.
Export SQLite Query Results to a CSV File
When using the SQLite command line shell, you can export your query results to a CSV file by using the .mode dot command in conjunction with the .output or .once commands.
You can also use the .system command to open that file.