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#11
 
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Re: rewriting LEFT JOINs as RIGHT JOINs -
04-24-2008
, 06:43 AM
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"Harry Skelton" <skelton.harry (AT) gmail (DOT) com> wrote in message news:480a17e5$0$22078$6e1ede2f (AT) read (DOT) cnntp.org... yawnmoth wrote: Out of curiosity, can every LEFT JOIN be rewritten as a query with RIGHT JOINs? It seems to me that if you just take the "leftmost" table and use that in the FROM part of a SELECT that all subsequent LEFT JOINs would need to be RIGHT JOINs... LEFT and RIGHT joins dictate precedence of the tables/queries. You could do it either way, but what data you get back will be different. If you do as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. |
Here my two cents:
It's not clear to me that the OP understands that A LEFT JOIN B is
equivalent to B RIGHT JOIN A... But if the OP does understand that, then
obviously (s)he means more than just changing every LEFT JOIN to a RIGHT
JOIN.
#12
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"Harry Skelton" <skelton.harry (AT) gmail (DOT) com> wrote in message news:480a17e5$0$22078$6e1ede2f (AT) read (DOT) cnntp.org... yawnmoth wrote: Out of curiosity, can every LEFT JOIN be rewritten as a query with RIGHT JOINs? It seems to me that if you just take the "leftmost" table and use that in the FROM part of a SELECT that all subsequent LEFT JOINs would need to be RIGHT JOINs... LEFT and RIGHT joins dictate precedence of the tables/queries. You could do it either way, but what data you get back will be different. If you do as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. |
Here my two cents:
It's not clear to me that the OP understands that A LEFT JOIN B is
equivalent to B RIGHT JOIN A... But if the OP does understand that, then
obviously (s)he means more than just changing every LEFT JOIN to a RIGHT
JOIN.
#13
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"Harry Skelton" <skelton.harry (AT) gmail (DOT) com> wrote in message news:480a17e5$0$22078$6e1ede2f (AT) read (DOT) cnntp.org... yawnmoth wrote: Out of curiosity, can every LEFT JOIN be rewritten as a query with RIGHT JOINs? It seems to me that if you just take the "leftmost" table and use that in the FROM part of a SELECT that all subsequent LEFT JOINs would need to be RIGHT JOINs... LEFT and RIGHT joins dictate precedence of the tables/queries. You could do it either way, but what data you get back will be different. If you do as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. |
Here my two cents:
It's not clear to me that the OP understands that A LEFT JOIN B is
equivalent to B RIGHT JOIN A... But if the OP does understand that, then
obviously (s)he means more than just changing every LEFT JOIN to a RIGHT
JOIN.
#14
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as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. How about making some sense out of it, Roy? Here my two cents: It's not clear to me that the OP understands that A LEFT JOIN B is equivalent to B RIGHT JOIN A... But if the OP does understand that, then obviously (s)he means more than just changing every LEFT JOIN to a RIGHT JOIN. |
mean more than that. It was the half-wit responder I was slamming.
Roy
#15
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as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. How about making some sense out of it, Roy? Here my two cents: It's not clear to me that the OP understands that A LEFT JOIN B is equivalent to B RIGHT JOIN A... But if the OP does understand that, then obviously (s)he means more than just changing every LEFT JOIN to a RIGHT JOIN. |
mean more than that. It was the half-wit responder I was slamming.
Roy
#16
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as you say, it is not merely changing the LEFT to a RIGHT, you are changing the entire SQL query. This can cause unforeseen problems, [...] are actually returned. Total nonsense. How about making some sense out of it, Roy? Here my two cents: It's not clear to me that the OP understands that A LEFT JOIN B is equivalent to B RIGHT JOIN A... But if the OP does understand that, then obviously (s)he means more than just changing every LEFT JOIN to a RIGHT JOIN. |
mean more than that. It was the half-wit responder I was slamming.
Roy
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