https://dev.mysql.com/innodb-memcached-porting-mysql.html
Consider these aspects of memcached applications when adapting an existing MySQL schema or application to use the daemon_memcached plugin: memcached keys cannot contain spaces or newlines, because these characters are used as separators in the ...
https://dev.mysql.com/choosing-types.html
All basic calculations (+, -, *, and /) with DECIMAL columns are done with precision of 65 decimal (base 10) digits. For optimum storage, you should try to use the most precise type in all cases. For example, if an integer column is used for values ...
https://dev.mysql.com/comparison-operators.html
Otherwise, if at least one argument is a DECIMAL value, they are compared as DECIMAL values. Whether a value is not within a range of values !=, <> Not equal operator NOT IN() Whether a value is not within a set of values NOT LIKE Negation of simple ...
https://dev.mysql.com/sys-ps-trace-thread.html
in_max_runtime DECIMAL(20,2): The maximum number of seconds (which can be fractional) to collect data. in_interval DECIMAL(20,2): The number of seconds (which can be fractional) to sleep between data collections. Dumps all Performance Schema data ...
https://dev.mysql.com/group-by-functions.html
The SUM() and AVG() functions return a DECIMAL value for exact-value arguments (integer or DECIMAL), and a DOUBLE value for approximate-value arguments (FLOAT or DOUBLE). The result type depends on whether the function argument values are evaluated ... This section describes group (aggregate) functions that operate on sets of ...
https://dev.mysql.com/insert.html
For example, inserting the string '1999.0e-2' into an INT, FLOAT, DECIMAL(10,6), or YEAR column inserts the value 1999, 19.9921, 19.992100, or 1999, respectively. For the FLOAT and DECIMAL columns, the string-to-number conversion considers the ...
https://dev.mysql.com/adding-udf.html
SQL Type C/C++ Type STRING char * INTEGER long long REAL double It is also possible to declare a DECIMAL function, but currently the value is returned as a string, so you should write the UDF as though it were a STRING function. To specify (for REAL ... For the UDF mechanism to work, functions must be written in C or C++ and your operating system must support dynamic ...
https://dev.mysql.com/data-types.html
D applies to floating-point and fixed-point types and indicates the number of digits following the decimal point (the scale). fsp applies to the TIME, DATETIME, and TIMESTAMP types and represents fractional seconds precision; that is, the number of ... MySQL supports a number of SQL data types in several categories: numeric types, date and time types, string (character and byte) types, spatial types, and the JSON data ...
https://dev.mysql.com/json-attribute-functions.html
The functions in this section return attributes of JSON values. An error occurs if the argument is not a valid JSON document. An empty array, empty object, or scalar value has depth 1. A nonempty array containing only elements of depth 1 or ...
https://dev.mysql.com/date-and-time-type-conversion.html
To some extent, you can convert a value from one temporal type to another. However, there may be some alteration of the value or loss of information. In all cases, conversion between temporal types is subject to the range of valid values for the ...