Most of the major DBMSs provide us with a way to find a string within a string using SQL. By this, I mean use a SQL query to find the position of a substring within a string.
There are several SQL functions that allow us to do this, including INSTR(), LOCATE(), POSITION(), and CHARINDEX(). The function you use will depend on your DBMS, and possibly whether or not you need to specify a starting position.
Most major RDBMSs provide ways for us to format numbers using SQL. Some provide only basic formatting capabilities, while others are more advanced.
Below are examples of formatting a number in some of the more popular RDBMSs.
Continue readingHere are two ways to format a number as a percentage in SQLite.
Continue readingIn SQLite, we can use the PRINTF() function or FORMAT() function to format numbers with leading zeros.
Most of the major RDBMSs provide several options for concatenating two or more strings.
CONCAT() function, which concatenates its arguments.CONCAT_WS() that allows you to specify a separator that separates the concatenated strings.Below are examples of each method.
Continue readingSQLite has a printf() function or format() function that allows us to format numbers according to a format string.
As from SQLite 3.18.0, it accepts a comma flag, which enables us to have comma separators at the thousands marks for integers.
Further work can be done to get it working with real/floating point numbers.
Continue readingSQLite has a PRINTF() function (and now a FORMAT() function) that allows us to format a number based on a format string. For example, we can use this to format the number to a given number of decimal places, plus add a currency symbol to it.
In SQLite, we can use the strftime() function to return datetime values in our chosen format.
Therefore, we can use it to extract the day, month, and year from a date.
Continue readingNormally if you need to drop a foreign key in SQL, you’d use the ALTER TABLE statement. But if you’re using SQLite, that’s not an option.
In SQLite, you can drop a table with the DROP TABLE statement.
You can optionally add the IF EXISTS clause to suppress any errors that might occur if the table doesn’t exist.
Also, if the table is referenced by a foreign key, there are a few things to be aware of.
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