About the JSON_MERGE() Function in MySQL

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In MySQL, JSON_MERGE() is a deprecated function that merges two or more JSON documents and returns the result.

It was deprecated in MySQL 8.0.3 and is subject to removal in a future release.

Fortunately, the JSON_MERGE_PRESERVE() function was added in MySQL 8.0.3 as a synonym for JSON_MERGE(), and it therefore does the same thing that JSON_MERGE() does/did.

Therefore, instead of using JSON_MERGE(), use JSON_MERGE_PRESERVE() instead.

Alternatively, you can use JSON_MERGE_PATCH(), which performs an RFC 7396 compliant merge of two or more JSON documents, without preserving members having duplicate keys.

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6 Ways to Fix “nextval: reached maximum value of sequence” in PostgreSQL

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If you’re getting an error that reads something like “nextval: reached maximum value of sequence “sequence1” (3)” in PostgreSQL, it’s probably because you’re trying to generate a new value from a sequence, but the sequence has already reached its maximum value.

We have quite a few options when it comes to dealing with this issue.

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Add a Column that Cycles Through a Range of Numbers in a Result Set in SQL Server

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If we ever need to assign repeating sequence numbers to a result set in SQL Server, we can use a sequence object with the appropriate arguments.

In particular, we can use the CYCLE argument to specify that the sequence will cycle through the range of numbers. In other words, once it reaches the end of the sequence, it starts again, and will continue to reiterate every time it completes the sequence.

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How CAST() Works in MySQL

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In MySQL, CAST() is a built in function that converts a value to another data type. It takes a value of one type and returns a value of the specified type.

You provide the value as an argument when you call the function, as well as the type that you’d like it converted to.

CAST() works similar to CONVERT(), except that the syntax used is slightly different.

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Fix “ERROR 1298 (HY000): Unknown or incorrect time zone…” in MySQL

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If you’re getting error 1298 that reads something like “ERROR 1298 (HY000): Unknown or incorrect time zone: ‘UTC’” in MySQL, it’s probably because you’re specifying a time zone name, but your MySQL installation hasn’t yet been configured for named time zones.

To fix this issue, be sure that your MySQL installation has been configured for named time zones.

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