Tag: how to

Fix “date/time field value out of range” in PostgreSQL

Posted on by Ian

If you’re getting an error that reads ‘date/time field value out of range‘ in PostgreSQL while using a function such as date_add(), date_subtract(), or date_trunc(), it’s probably because the date value you’re passing to the function is an invalid date.

It’s possible that you’ve got the month and day in the wrong order.

To fix this issue, be sure that you pass a valid date. It may be that all you need to do is switch the day and the month around. Or it could be that you need to change your datestyle setting.

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Fix Error “cannot take logarithm of zero” in PostgreSQL

Posted on by Ian

If you’re getting an error that reads “ERROR: cannot take logarithm of zero” when using either the log() function or log10() function in PostgreSQL, it’s probably because you’re passing an argument of zero.

These functions require a value greater than zero. This is true even for the base argument of the log() function (the argument that specifies which base to use).

To fix this issue, be sure to pass a value greater than zero to these functions.

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5 String Functions that Return Length in PostgreSQL

Posted on by Ian

PostgreSQL provides us with a handful of string functions that return the length of a given string.

But the result between these functions can be different, depending on which function we use. That’s because the “length” can be different, depending on what we’re measuring. Are we talking about the number of characters in the string? Or the number of bytes in the string? Or perhaps we want to know the number of bits in the string.

The function we use will depend on which of the above we’re trying to measure. Below are five functions that cater for each of the above questions.

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Create a Multi-Dimensional Array from a Query in PostgreSQL

Posted on by Ian

In PostgreSQL, we can use array constructors to create arrays that contain elements that we specify. We can populate the array from literal values, or we can let a query provide the values.

We can also create multi-dimensional arrays. When populating the array from a query, we can use multiple subqueries to create each sub-array. Therefore we can create a multi-dimensional array from a query.

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Fix Error “cannot take logarithm of a negative number” in PostgreSQL

Posted on by Ian

If you’re getting an error that reads “ERROR: cannot take logarithm of a negative number” when using either the log() function or log10() function in PostgreSQL, it’s probably because you’re passing a negative value to the function.

These functions require a value greater than zero. This is true even for the base argument of the log() function (the argument that specifies which base to use).

To fix this issue, be sure to pass a value greater than zero to these functions.

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Fix ‘time zone … not recognized’ in PostgreSQL

Posted on by Ian

If you’re getting an error that reads something like ‘time zone “US/New_York” not recognized‘ in PostgreSQL while using a function such as date_add(), date_subtract() or date_trunc(), it’s probably because you’re specifying an unsupported time zone.

If you specify a time zone, it must be one that’s recognised by the system.

To fix this issue, either provide a recognised time zone or omit the time zone argument altogether (assuming this is a valid option for the situation).

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Fix “function array_shuffle(numeric) does not exist” in PostgreSQL

Posted on by Ian

If you’re getting an error that reads “function array_shuffle(numeric) 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.

More specifically, this error message implies that you’re passing a numeric type. The same error can occur when passing other non-array types (such as integer), but the solution is the same.

The argument for this function must be an array.

To fix this error, replace the numeric value with an array value when calling the array_shuffle() function.

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Fix Error “cannot determine type of empty array” in PostgreSQL

Posted on by Ian

If you’re getting an error that reads “cannot determine type of empty array” in PostgreSQL, it could be that you’re trying to create an empty array without specifying the array type.

It’s impossible to create an array with no type, and so if we want to create an empty array, then we need to specify the type or add items to determine the type.

To fix this issue, either specify the array type for the empty array, or add items to the array.

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