If you’re getting an error that reads something like “The sequence object ‘…’ has reached its minimum or maximum value. Restart the sequence object to allow new values to be generated.“, it’s probably because you’re using a sequence that’s reached the minimum or maximum value specified in its definition.
Continue readingAuthor: Ian
Generate a CREATE TABLE Script for an Existing Table in MariaDB
We can use MariaDB’s SHOW CREATE TABLE statement to generate a CREATE TABLE script for existing tables in the database. This allows us to recreate the table without having to manually type out the table’s definition.
The statement requires SELECT privilege for the table.
Fix “NEXT VALUE FOR function cannot be used directly in a statement that contains an ORDER BY clause unless the OVER clause is specified.” in SQL Server (Error Msg 11723)
If you’re getting an error that reads “NEXT VALUE FOR function cannot be used directly in a statement that contains an ORDER BY clause unless the OVER clause is specified” in SQL Server, it’s probably because you’re trying to sort the results of a query that uses the NEXT VALUE FOR function without using the OVER clause.
How to Allow Duplicate Fields when using HRANDFIELD in Redis
By default, Redis’s HRANDFIELD command returns distinct fields. In other words, it won’t return the same field multiple times – each field that’s returned by the command will only be returned once.
However, we can override this behaviour by using an negative count value for the count argument.
When we pass a negative count argument, the HRANDFIELD command allows non-distinct fields to be returned.
2 Ways to Clone a Table in SQL Server
There are various methods for cloning/copying tables with SQL, but not all methods are supported by all RDBMSs.
Below are two options for cloning a table in SQL Server.
Continue readingHow to Return Data from Modified Rows in PostgreSQL
In PostgreSQL, we can use the RETURNING clause to return data that was modified during an UPDATE, INSERT, or DELETE operation. This allows us to see the data that was modified without having to perform a separate query to retrieve that data.
How to Reset a Sequence in SQL Server
In SQL Server, we can use sequences to generate sequence numbers that increment by a specified amount. This means that any new number generated by the sequence will be the next sequential increment as specified in the sequence’s definition.
Normally, this is exactly what we want. We want each number to adhere to the increment that we specified when defining the sequence.
But what if we want to reset the sequence, so that the numbering starts all over again? In other words, we want to restart the sequence from the beginning. Or what if we want to reset the sequence so that it increments in a different range?
Fortunately, we can reset a sequence with the ALTER SEQUENCE statement.
Fix “WRONGTYPE Operation against a key holding the wrong kind of value” when using HSTRLEN in Redis
If you’re getting an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when using the Redis HSTRLEN command, it’s probably because you’re running the command against a key that doesn’t contain a hash.
Fix “ERR syntax error” When using HRANDFIELD in Redis
If you’re getting an error that reads “ERR syntax error” when using the HRANDFIELD command in Redis, it could be that you’re passing the wrong number of arguments. At the time of writing, the HRANDFIELD command requires at least one argument, and accepts up to three arguments.
5 Ways to Check if a Field Exists in a Redis Hash
Redis provides some easy ways to check whether or not a field exists in a given hash. Here are five commands that we can use to check for the existence of a field in a given hash.
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