Using OUTER , WHERE or Simply JOIN

Using OUTER , WHERE or Simply JOIN

Question:
Does it make a difference in placing an OUTER or simply a JOIN or a WHERE?

Using WHERE:

select tb01_field01,tbl01_field02    from tb01,tb02      where tb01_field01 = tb02_field01

Using JOIN:

SELECT TB01_FIELD01,TB01_FIELD02      FROM TB01      JOIN TB02      ON TB01_FIELD01 = TB02_FIELD01

How do I use OUTER to do the same thing as the commands above? Is it faster with OUTER?

Answer:
Your second instance, “Using JOIN”, is not valid SQL in Informix. It should be:

SELECT TB01_FIELD01,TB01_FIELD02      FROM TB01, TB02      WHERE TB01_FIELD01 = TB02_FIELD01

The OUTER statement only deals with what happens when one of the tables has rows that are not matched by the JOIN. It is probably a little slower than a regular JOIN, because it has to include rows that would not be returned in a non-OUTER join.

Share the Post:
data observability

Data Observability Explained

June 8, 2023

Data is the lifeblood of any successful business, as it is the driving force behind critical decision-making, insight generation, and strategic development. However, due to its intricate nature, ensuring the

Heading photo, Metadata.

What is Metadata?

June 1, 2023

What is metadata? Well, It’s an odd concept to wrap your head around. Metadata is essentially the secondary layer of data that tracks details about the “regular” data. The regular

Show More