The original paragraph in the article " A Case in which MySQL's Implicit Conversion Causes Weird Phenomenon " reads,
上述例子中 "测试a" 会截成 ""，因此 a=0 ，才会返回字段不为空的。A friend left a message saying, is this sure correct? "Test a" should be converted to 0, not ""?
I think this part is a bit vague, but the conclusion is correct.
Because of the data type problem, "test a" will be converted into a numeric type, and MySQL will automatically truncate it. What should be truncated into "" (empty), it just means that "" and 0 are equal, which can be verified through CAST, "test a" " and '' (empty) are converted to numeric types and both are 0,
select cast('测试a' AS UNSIGNED), CAST('' AS UNSIGNED);
If it is more accurate, it should be said that "test a" is automatically cut into "" (empty), "" and 0 are equal, so we get "a=0".
When it comes to technology, you still have to be more rigorous.
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