some question about the result.

Anon

table 1 and table 2 have no fields in common,my query is:
select * from table1,table2 where table1.col like '$search%' or table2.col like '$search%';

what's the result?
who can give me a example about select in mutitable.

Thanks a lot.

Anon

Hello Jason,

This example you put here is a cartesian product. The DB will output a cartesian produict between table 1 and table2.

If you have a table
PRODUCT
PRODUCT_ID
PRODUCT_NAME

with 10 rows

and a table
PERSON
PERSON_ID,
PERSON_NAME

with 11 rows

the select * from PRODUCT, PERSON

will return 10*11=110 rows with all data from product and person.

Regrads

Anon

Hello Jason,

This example you put here is a cartesian product. The DB will output a cartesian produict between table 1 and table2.

If you have a table
PRODUCT
PRODUCT_ID
PRODUCT_NAME

with 10 rows

and a table
PERSON
PERSON_ID,
PERSON_NAME

with 11 rows

the select * from PRODUCT, PERSON

will return 10*11=110 rows with all data from product and person.

Regrads

Anon

Hello Jason,

This example you put here is a cartesian product. The DB will output a cartesian produict between table 1 and table2.

If you have a table
PRODUCT
PRODUCT_ID
PRODUCT_NAME

with 10 rows

and a table
PERSON
PERSON_ID,
PERSON_NAME

with 11 rows

the select * from PRODUCT, PERSON

will return 10*11=110 rows with all data from product and person. Each row with 4 fields(PERSON_ID, PERSON_NAME, PRODUCT_ID, PRODUCT_NAME). You may figure out something like: for each ocurrence on an product will bring all persons.

Regrads

jason wrote:

table 1 and table 2 have no fields in common,my query is:
select * from table1,table2 where table1.col like '$search%' or table2.col like '$search%';

what's the result?
who can give me a example about select in mutitable.

Thanks a lot.

Anon

I don't know the answer to your question, but I would probably turn it into 2 separate queries to get me by.

result1 = SELECT * FROM table1 WHERE col1 LIKE ('Wahtever')

result2 = SELECT * FROM table2 WHERE col1 LIKE ('Wahtever')