In PostgreSQL, the quote_nullable() function returns a given string suitably quoted to be used as a string literal in a SQL statement string. It returns the actual string NULL if the argument is null.
Any embedded single-quotes and backslashes are properly doubled.
In PostgreSQL, we can use the overlay() function to replace a substring within a string. The function allows us to be very specific with regards to where in the string to start the operation and how much of it should be replaced.
PostgreSQL has a couple of functions that enable us to get the position or positions of a given value in an array. One of them – array_position() – returns the position of just the first occurrence (as an integer), while the other function – array_positions() – returns the position of all occurrences (as an array).
So these functions are aptly named – one is singular and the other is plural.
But this isn’t the only difference. The array_position() function allows us to specify a start position, while array_positions() doesn’t.
In PostgreSQL, the ltrim() function trims the left side of a string. We can trim blank spaces or we can specify certain characters to trim.
It removes the longest string containing only characters from the ones we specify. If we don’t specify any characters, then it removes blank spaces.
In PostgreSQL, we can use the rtrim() function to trim the right side of a string. We can trim blank spaces or we can specify certain characters to trim.
It removes the longest string containing only characters from the ones we specify. If we don’t specify any characters, then it removes blank spaces.
In PostgreSQL, the trim() function can be used to trim both sides, or a specified side, of a string. We can trim blank spaces or we can specify certain characters to trim.
It removes the longest string containing only characters from the ones we specify. If we don’t specify any characters, then it removes blank spaces.
We can use the array_remove() function in PostgreSQL to remove elements from an array.
We pass two arguments when calling the function; the first is the array and the second argument is the element to remove. All occurrences of the specified element are removed.
The function returns an identical array, but without the specified element/s.
In PostgreSQL, the octet_length() function returns the number of bytes in a given string. We pass the string as an argument and the function returns the number of bytes in that string.
PostgreSQL has a bit_length() function that returns the number of bits in a given string. We pass the string as an argument and the function returns the number of bits in that string.
In PostgreSQL, we can use the array_cat() function to concatenate two arrays.
We pass both arrays as arguments when we call the function.