php - mysql substitution variables -

i don't want open new question such basic question need help. im studying mysql , started substitution variables

consider simple statement:

  select empid, surname      employees         empid = &empid 

oracle gives me error not variables bound. please, enlighten me wrong statement?

see oracle application express docs: https://docs.oracle.com/cd/e14373_01/user.32/e13370/sql_proc.htm#aeutl228

bind variables prefixed colon.

so change query to:

 select empid, surname      employees         empid = :empid 

when run query, popup window asking supply value of :empid.