str 函数 将小数转换为varchar类型

When you want to convert from float or real to character data, using the STR string function is usually more useful than CAST( ). This is because STR enables more control over formatting.

Syntax

STR ( float_expression [ , length [ , decimal ] ] )

Arguments

float_expression
Is an expression of approximate numeric (float) data type with a decimal point.

length
Is the total length. This includes decimal point, sign, digits, and spaces. The default is 10.

decimal
Is the number of places to the right of the decimal point. decimal must be less than or equal to 16. If decimal is more than 16 then the result is truncated to sixteen places to the right of the decimal point.

Return Type
　　Varchar,
　　To convert to Unicode data, use STR inside a CONVERT or CAST conversion function
示例

SELECT STR(123.45, 6, 1);

结果是 123.5，类型是Varchar