Hi,
According to the documentation (Sqlite + standard Ansi),
queries that should be supported like :
SELECT *
FROM A JOIN (B JOIN C ON B.ID = C.ID) ON A.ID = B.ID
are still not supported whereas badly formed queries like :
SELECT *
FROM A JOIN (B JOIN C ON B.ID = C.ID) AS D ON A.ID = D.ID
work !
anyone to fix this ?
Mathieu
-----Message d'origine-----
De : sqlite-users-boun...@sqlite.org [mailto:sqlite-users-boun...@sqlite.org]
De la part de Mathieu TAUZIN Envoyé : lundi 26 mars 2012 15:53 À :
sqlite-users@sqlite.org Objet : [sqlite] Parser bug on sub joins when on right
side of the join operator
Hi,
According to their definition
(http://sqlite.org/syntaxdiagrams.html#single-source) , Join sources (named
single-source) are either :
* a table or view with an optional alias and/or with an
optional index
* a sub query with an optional alias
* a sub join (with no alias)
In SQLite parser.y source code we can find on line 496 the grammar rule
handling those three cases (in the same order)
<snippet line='496'>
...
seltablist(A) ::= stl_prefix(X) nm(Y) dbnm(D) as(Z) indexed_opt(I) on_opt(N)
using_opt(U). {
A = sqlite3SrcListAppendFromTerm(pParse,X,&Y,&D,&Z,0,N,U);
sqlite3SrcListIndexedBy(pParse, A, &I); }
seltablist(A) ::= stl_prefix(X) LP select(S) RP
as(Z) on_opt(N) using_opt(U). {
A = sqlite3SrcListAppendFromTerm(pParse,X,0,0,&Z,S,N,U);
}
seltablist(A) ::= stl_prefix(X) LP seltablist(F) RP
as(Z) on_opt(N) using_opt(U). {
if( X==0 && Z.n==0 && N==0 && U==0 ){
A = F;
}else{
Select *pSubquery;
sqlite3SrcListShiftJoinType(F);
pSubquery = sqlite3SelectNew(pParse,0,F,0,0,0,0,0,0,0);
A = sqlite3SrcListAppendFromTerm(pParse,X,0,0,&Z,pSubquery,N,U);
}
}
...
</snippet>
Case 1 and 2 are handled properly but as you can see the third definition (wich
should deal with sub joins) contains mistakes :
#1 : It allows an as clause after the parenthesis
#2 : on the right of a join operator (else { ... }) it
generates a subquery instead of merging F (which is a seltabList, not a sub
query) with X into A.
I wish I could propose a fix but I have no skills in C/yacc.
Hope this will help anyway.
Thanks
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