$"$SQL : I have created $3$ tables $($table $1,$ table $2$ and view $3)$ in a database. I would like to create a trigger that shows the message $""$none available"" and prevents insertion on on table $1$ when view $3$ is empty.

I have tried this:

create trigger none$\_$available before insert on table$\_1$ for each row if $($not exis UJ$20$ ts $($ select $1$ from available$))$ begin print $""$none available"" end;

but I get a syntax error at $""$if$""$

I would like to know how to create this trigger or something similar that would not allow insertion on table $1$ when view $3$ is empty."