Oracle set Define Off

The default "&" in Sql/plus represents an alternative variable, that is, Sql/plus will ask you to enter an alternate value whenever the symbol appears in the command.
This means that you cannot enter a string containing the symbol into the database or assign it to a variable.
As the string "You&i" system will be interpreted as a "you" beginning of the string, it will prompt you to enter the value of the substitution variable i, if you enter I, the final string into "YouI".

Set define off this function, "&" as a normal character, as in the above example, the final character is "You&i"

Oracle set Define Off