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.
functions
Difference Between ARRAY_POSITIONS() and ARRAY_POSITION() in PostgreSQL
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.
Using LTRIM() in PostgreSQL
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.
Understanding RTRIM() in PostgreSQL
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.
A Quick Look at the TRIM() Function in PostgreSQL
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.
Let’s Look at PostgreSQL’s ARRAY_REMOVE() Function
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.
Understanding OCTET_LENGTH() in PostgreSQL
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.
A Quick Look at the BIT_LENGTH() Function in PostgreSQL
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.
A Quick Intro to ARRAY_CAT() in PostgreSQL
In PostgreSQL, we can use the array_cat() function to concatenate two arrays.
We pass both arrays as arguments when we call the function.
Understanding the BTRIM() Function in PostgreSQL
PostgreSQL has a function called btrim() that we can use to trim both sides 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 from both sides.
We provide the string as the first argument, and the (optional) characters as the second.