Android中大写字母区分大小写

Question

In my MYSQL database saved email is jiaweitan05@gmail.com . When I login with all capital case for email like JIAWEITAN05@GMAIL.COM it is succesfully login since every letter is correct. But how should I do for capital sensitive case for email input. So that when JIAWEITAN05@GMAIL.COM of user input while comparing SQL query with small capital jiaweitan05@gmail.com is not match because of capital case sensitive. Or should I consider of implement this feature?

Answer 1

You can check the whether the email contains capital letter like this :

boolean isUpperCase =false;
for(int i=0;i<string.length;i++)
{
  isUpperCase = Character.isUpperCase("My String".charAt(i));

}

 if(isUpperCase==true)
    {
    // give error to user
    }

Answer 2

你可以尝试像

SELECT * FROM table_name WHERE UPPER(column_name) = UPPER('jiaweitan05@gmail.com')

Answer 3

Try using case-insensitive collation . To c ause a case-sensitive comparison of nonbinary strings to be case insensitive, use COLLATE to name a case-insensitive collation

Select * from table
where email = 'JIAWEITAN05@GMAIL.COM' collate utf8_bin

You have to change your column name

email varchar(size) collate utf8_bin

A binary string is case sensitive in comparisons. To compare the string as case insensitive, convert it to a nonbinary string and use COLLATE to name a case-insensitive collation

Example:

mysql>SET @s = BINARY 'aBcD';
mysql> SELECT @s, LOWER(@s), UPPER(@s);

+------+-----------+-----------+
| @s   | LOWER(@s) | UPPER(@s) |
+------+-----------+-----------+
| aBcD | abcd      | ABCD      |
+------+-----------+-----------+