SQL statement execute sequence?

[xrapidx]

does anyone have a handy link on the execute sequence of a SQL statement, i.e. WHERE first, JOIN second, GROUP BY third etc, etc.

Having a discussion (argument) here at work - and don't have my SQL books with me - google also isn't being very helpful.

 

[Other Pineapple Smurf]

What do mean? The order

Just check Postgresql or Mysql domain?

SELECT { ... }
FROM ({ tables } INNER JOIN|OUTER JOIN {tables} ON|USING ) ...
WHERE { condition }
GROUP BY { columns/fields }
ORDER BY { columns/fields }
HAVING { Select statement condition ie COUNT(*) > 10 }
;

 

[Other Pineapple Smurf]

Oops forgot UNION

SELECT { ..... } FROM .... WHERE ..... GROUP BY .... ORDER BY .... HAVING ...
UNION
SELECT { ..... } FROM .... WHERE ..... GROUP BY .... ORDER BY .... HAVING ...
;

 

[xrapidx]

e.g.

SELECT  {columns}
FROM    TABLE-A
JOIN      TABLE-B
ON        TABLE-A.COL-A = TABLE-B.COL-A
WHERE   TABLE-A.COL-B = 1
AND      TABLE-B.COL-B = 2

What is applied first, the JOIN condition or the WHERE condition.

 

[joe_cal]

hi everyone, first post here

from (first get all the data)
where (filter out any rows you dont want)
group by (group the data)
having (filter on groups)
select (filter out columns you dont want)
order by (last part to be run)

 

[ABCpt]

hi everyone, first post here

from (first get all the data)
where (filter out any rows you dont want)
group by (group the data)
having (filter on groups)
select (filter out columns you dont want)
order by (last part to be run)

and I would suppose the from would include the joins as well, otherwise you cannot get the data.

 

[joe_cal]

yup

 

[xrapidx]

So join before where?

 

[<?php?>]

hi everyone, first post here

from (first get all the data)
where (filter out any rows you dont want)
group by (group the data)
having (filter on groups)
select (filter out columns you dont want)
order by (last part to be run)

Nope, SELECT-> FROM -> JOIN -> WHERE -> ORDERBY

 

[<?php?>]

see: http://www.w3schools.com/sql/default.asp

 

[joe_cal]

So join before where?

yes, join is part of the "from" which is done before the "where" part

 

[joe_cal]

Nope, SELECT-> FROM -> JOIN -> WHERE -> ORDERBY

OP is not asking for the syntax. wants to know the order in which the parts of a sql statemnt is executed.

 

[xrapidx]

yes, join is part of the "from" which is done before the "where" part

Thanks - thats basically been my argument - and confirmed correct

 

[<?php?>]

OP is not asking for the syntax. wants to know the order in which the parts of a sql statemnt is executed.

:erm: That's what I said, -> -> ->