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.
Continue readingIf you’re getting an error that reads “function array_shuffle(integer, integer) does not exist” when using the array_shuffle() function in PostgreSQL, it’s probably because the argument you’re passing to the function is not an array.
Actually, the error message implies that you’re passing multiple integer values (two in this case, but it could be more), separated by a comma. Perhaps you’re trying to pass an array of integers, but you haven’t provided them in an array. Or perhaps you’re passing the wrong column or variable. Either way, the argument for this function must be an array.
To fix this error, replace the integer values with a single array value when calling the array_shuffle() function.
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.
If you’re getting a PostgreSQL error that reads “op ANY/ALL (array) requires array on right side” it’s probably because you’re passing a non array to the ANY() or ALL() construct.
These constructs require an array to be included in the parentheses, and so passing a non array returns an error.
To fix this issue, be sure to pass an array when using these functions.
Continue readingIn 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.
Continue readingIn 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.
Continue readingIn 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.
Continue readingIf you’re getting an error that reads ‘date field value out of range‘ in PostgreSQL while using the make_date() function, it’s probably because one or more of the date parts you’re providing is out of range for that date part.
It’s possible that you’ve got the month and day in the wrong order.
To fix this issue, be sure that each date part you provide is within the valid range for that date part. It may be that all you need to do is switch the day and the month around.
Continue readingWe 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.
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