BigQuery: How do I check for every string element of column1 whether it is contained in column2?

Question

I am using BigQuery. My data looks like this, I start with Table1 and Table2:

Table1

Str1
"a"
"b"

Table2

id	Str2
1	"car"
2	"apple"
3	"banana"
4	"bob"

How can I design my query to get Table3?

It has the Table2.id if the value from Table1 is found as substring in Table2.Str2.

Table3

a	b
1	0
2	0
3	3
0	4

Thank you!

Answer 1

Consider below approach

select * from (
  select id, str1, regexp_contains(str2, str1) contained
  from table2, table1
)
pivot (min(contained) for str1 in ('a', 'b'))        

if applied to sample data in your question - output is

In case if you actually need output look exact as in your question - use below

select if(a, id, 0) a, if(b, id, 0) b from (
  select id, str1, regexp_contains(str2, str1) contained
  from table2, table1
)
pivot (min(contained) for str1 in ('a', 'b'))           

in this case - output is