Mybatis # {} and the {$} using

meaning

# {}: A placeholder

{} $: As splicing character

the difference:

　　usage

　　# {}: Parameter placeholder? That precompiled sql

        $ {} Is the replacement string, string concatenation

　　Implementation process

　　# {}: Dynamic analysis -> precompiled -> Run

　　 $ {}: Dynamic analysis -> Compiler -> Run

　　Variable Substitution

　　# {}: Variable substitution is in the DBMS (database management system), the corresponding variables will automatically add '

　　 {} $: Variable substitution DBMS outside it, will not variables corresponding with ''

　　sql injection

　　{#} Sql injection can be prevented

　　$ {} May not prevent sql injection

skills

　　Whether a single parameter or multiple parameters, all recommended @param ( "")

　　 # {} Can place as much as possible using the # {}, {} decrease $

　　 Table name as a parameter must be $ {}

         When the order by, must $ {}

         When use is to be noted $ {} with or without single quotation marks