In MySQL, we can use the sys.ps_is_thread_instrumented() function to check whether Performance Schema instrumentation for a given connection ID is enabled.
The function returns YES or NO, depending on whether the instrumentation is enabled for the given connection. It can also return UNKNOWN if the connection ID is unknown, and NULL if the connection ID is NULL.
In MySQL, we can use the sys.version_patch() function to return the patch release version of the MySQL server.
For example, if we’re using MySQL 8.0.33, sys.version_patch() returns 33.
In MySQL, we can use the sys.version_minor() function to return the minor release version of the MySQL server.
In MySQL, we can use the sys.version_major() function to return the major release version of the MySQL server.
In MySQL, we can use the PS_CURRENT_THREAD_ID() function to get the Performance Schema thread ID assigned to the current connection.
The PS_CURRENT_THREAD_ID() function was added in MySQL 8.0.16, and it does the same thing as PS_THREAD_ID(CONNECTION_ID()).
In MySQL, format_pico_time() is a Performance Schema function that converts a numeric Performance Schema latency or wait time in picoseconds into a human-readable format. It returns a string consisting of a value and a units indicator.
In MySQL, the DEFAULT() function returns the default value for a given column in the database.
If the column doesn’t have a default value, an error is returned.
Continue readingIn MySQL, the data directory stores information managed by the MySQL server. Each subdirectory of the data directory is a database directory and corresponds to a database managed by the server.
If you ever need to find out where the data directory is located on your MySQL implementation, below are some options to try.
Continue readingIf you’ve been using MySQL for any decent amount of time, it’s likely you’ll be familiar with error 1055 that reads something like “Expression #N of SELECT list is not in GROUP BY clause and contains nonaggregated column…“, where #N is the expression number of an expression/column in your SELECT list.
This error can occur when we include a column in the SELECT list, but we omit it from the GROUP BY clause.
There are several ways we can go about resolving this issue. Below are six options for dealing with this issue.
Continue readingIn MySQL, we can include the AUTO_INCREMENT attribute within a column definition in order to create an auto-incrementing column.
Generally, when we do this MySQL will automatically generate a value for us whenever we insert a new row into the table. I say “generally” because we can still explicitly insert our own value if that’s required.
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