if statement - Add column with FK to an existing table in MySQL 5.6 -
good day everyone. hope can helps me in experiments.
i have simple table needs , it's have data inside.
create table if not exists main.test ( id int(11) not null, name varchar(30) not null, date_created timestamp not null, primary key (id));
but should update table adding column fk_.
how can check if table had has field fk_? if such column not exist do:
alter table main.test add column fk int(11), add foreign key (fk) references test2(id_test2)
as use java decision of problem using resultset.
resultset set = statement.executequery(query); set.next(); int result = set.getint(1); //it return 1 row set.close();
and sql-query:
select count(column_name) information_schema.columns table_schema = 'main' , table_name = 'test' , column_name = 'fk";
when i'll result can decide query should use.
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