mysql 数据库字符串查询6920533939703649410 与6920533939703649419能互查结果

看代码感觉应该是数据类型不对导致的自动转换，可以把查询的数字变成字符串，应该就能解决问题.

select '6920533939703649410' + 0, '6920533939703649419' + 0, cast('6920533939703649410' as double)

你的 order_no 是 int 类型么？ 不是 int 类型你用 int 类型去查什么？

When an operator is used with operands of different types, type conversion occurs to make the operands compatible. Some conversions occur implicitly.

If one or both arguments are NULL, the result of the comparison is NULL, except for the NULL-safe <=> equality comparison operator. For NULL <=> NULL, the result is true. No conversion is needed.

If both arguments in a comparison operation are strings, they are compared as strings.

If both arguments are integers, they are compared as integers.

Hexadecimal values are treated as binary strings if not compared to a number.

If one of the arguments is a TIMESTAMP or DATETIME column and the other argument is a constant, the constant is converted to a timestamp before the comparison is performed. This is done to be more ODBC-friendly. This is not done for the arguments to IN(). To be safe, always use complete datetime, date, or time strings when doing comparisons. For example, to achieve best results when using BETWEEN with date or time values, use CAST() to explicitly convert the values to the desired data type.

有没有一种可能是你查询值没有带引号导致的 :smiley:

没加引号导致的类型转换. mysql小窍门: 查询宁可引号, 也不要不加引号

他们说的对

除此之外，还需要注意，如果字段类型是 varchar、char 等字符串类型时，如果你给定一个数字值去查询时，会导致这一列无法走到索引，反之却不会。

• MySQL :: MySQL 8.0 Reference Manual :: 12.3 Type Conversion in Expression Evaluation

字符串类型不带' 号，你传入int 类型， 会发生内部隐式转换，给你转成整型，如果长度超过 整型的 比如int 能代表的最大数值，你那个字符串的数字就是一样的结果了

bigint 遇到 一个设11 一个设16 然后11的存了13 16的存13。 navicat 里查询时 显示不一样但是用cast 转换为字符串后 显示的一样 导致 查用int查的时候 又相等了。用int 也得小心长度 最好设大了