Question

I’m trying to skip an INSERT in a particular case, where one of two involved values is a specific value:

// this can work if Beech allready exists
INSERT IGNORE INTO my_table (col_wood_name, col_type)
VALUES ("Beech", 0)

// this should be skipped if Beech allready exists with col_type = 1
INSERT IGNORE INTO my_table (col_wood_name, col_type)
VALUES ("Beech", 1)

my_table:
id      col_wood_name     col_type       other_column_1     other_column_2     etc_cols
1       Beech             0              ...                ...                ...
2       Fir               0              ...                ...                ...
3       Beech             1              ...                ...                ...
4       Pine              1              ...                ...                ...
5       Beech             1 // here is my problem, how can I avoid to insert a tree if col_type == 1?
6       Beech             0 // it's ok because col_type == 0

how can I avoid to insert a tree name if col_type == 1?

I know I can create unique key on col_wood_name and col_type using something like:

ALTER TABLE my_table ADD UNIQUE(col_wood_name, col_type);

but this is incomplete because this should work only if col_type is 1, how can I solve it?

Answer 1

AFAIK, there is no way of doing that in one query. Use Stored Procedures or an additional query in your application.