The default value of M is When such a column is assigned a value with more digits following the decimal point than are allowed by the specified scale, the value is converted to that scale. The precise behavior is operating system-specific, but generally the effect is truncation to the allowable number of digits. The BIT data type is used to store bit-field values.
M can range from 1 to To specify bit values, b' value ' notation can be used. For example, b'' and b'' represent 7 and , respectively. See Section 8. If you assign a value to a BIT M column that is less than M bits long, the value is padded on the left with zeros. For example, assigning a value of b'' to a BIT 6 column is, in effect, the same as assigning b''.
When asked to store a value in a numeric column that is outside the data type's allowable range, MySQL's behavior depends on the SQL mode in effect at the time.
For example, if no restrictive modes are enabled, MySQL clips the value to the appropriate endpoint of the range and stores the resulting value instead. In nonstrict mode, when an out-of-range value is assigned to an integer column, MySQL stores the value representing the corresponding endpoint of the column data type range. When a floating-point or fixed-point column is assigned a value that exceeds the range implied by the specified or default precision and scale, MySQL stores the value representing the corresponding endpoint of that range.
If the result would otherwise have been negative, it becomes the maximum integer value. If strict SQL mode is enabled, an error occurs and the column remains unchanged. When MySQL is operating in strict mode, these statements fail, and some or all of the values will not be inserted or changed, depending on whether the table is a transactional table and other factors.
For details, see Section 5. Special accommodations are needed to avoid accidentally inserting 0's for these values when integrating a MySQL database with a scientific application that generates these values. In this case, MySQL performs a string-to-number conversion that involves no intermediate double-precision representation.
This means that if you multiply two big integers or results from functions that return integers , you may get unexpected results when the result is larger than M is the total number of digits the precision and D is the number of digits after the decimal point the scale.
The decimal point and for negative numbers the - sign are not counted in M. If D is 0, values have no decimal point or fractional part. The maximum number of supported decimals D is If D is omitted, the default is 0. If M is omitted, the default is A small single-precision floating-point number. Permissible values are These are the theoretical limits, based on the IEEE standard. The actual range might be slightly smaller depending on your hardware or operating system. M is the total number of digits and D is the number of digits following the decimal point.
If M and D are omitted, values are stored to the limits permitted by the hardware. A single-precision floating-point number is accurate to approximately 7 decimal places. See Section B. A floating-point number. A normal-size double-precision floating-point number. A double-precision floating-point number is accurate to approximately 15 decimal places.
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