https://dev.mysql.com/precision-math-numbers.html
In MySQL, types that are synonymous with FLOAT or DOUBLE are DOUBLE PRECISION and REAL. The scope of precision math for exact-value operations includes the exact-value data types (integer and DECIMAL types) and exact-value numeric literals.
https://dev.mysql.com/subquery-optimization-with-exists.html
This is a problem because many real world subqueries become very slow unless the equality can be pushed down. To help the query optimizer better execute your queries, use these suggestions: Declare a column as NOT NULL if it really is. Certain ...
https://dev.mysql.com/differences-from-ansi.html
The CAST() function does not support cast to REAL or BIGINT. We try to make MySQL Server follow the ANSI SQL standard and the ODBC SQL standard, but MySQL Server performs operations differently in some cases: There are several differences between ...
https://dev.mysql.com/processlist-table.html
For a slave SQL thread, the value is the number of seconds between the timestamp of the last replicated event and the real time of the slave machine. The PROCESSLIST table provides information about which threads are running. This is the same type ...
https://dev.mysql.com/mysql-cluster-sql-statements.html
You can also query the tables in the ndbinfo information database for real-time data about many NDB Cluster operations. This section discusses several SQL statements that can prove useful in managing and monitoring a MySQL server that is connected ...
https://dev.mysql.com/c-api-data-structures.html
This section describes C API data structures other than those used for prepared statements, the asychronous interface, or the replication stream interface. For information about those, see Section 28.7.9, “C API Prepared Statement Data ...
https://dev.mysql.com/proxy-users.html
The plugin that authenticates a given connection may request that the connecting (external) user be treated as a different user for privilege-checking purposes. This enables the external user to be a proxy for the second user; that is, to assume the ...
https://dev.mysql.com/show-processlist.html
For a slave SQL thread, the value is the number of seconds between the timestamp of the last replicated event and the real time of the slave machine. SHOW [FULL] PROCESSLIST SHOW PROCESSLIST shows which threads are running. If you have the PROCESS ...
https://dev.mysql.com/type-conversion.html
In all other cases, the arguments are compared as floating-point (real) numbers. When an operator is used with operands of different types, type conversion occurs to make the operands compatible. For example, MySQL automatically converts strings to ...
https://dev.mysql.com/udf-features.html
The MySQL interface for user-defined functions provides the following features and capabilities: Functions can return string, integer, or real values and can accept arguments of those same types. You can define simple functions that operate on a ...
