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Make PredicateStitcher implement more AstVisitor nodes

See original GitHub issue

PredicateStitcher should be able to re-construct the entire AST of a Query after mutating a Table node with predicates stitched.

The general idea is to implement the AST ancestors of Table upwards till Query, plus the AST ancestors of every base node of every AST ancestor of Table. To put it recursively, if node is in the set, also include the AST parent of node as well as the AST parents of the node’s base classes.

The following AstVisitor methods are yet to be implemented.

visitExcept() visitIntersect() visitSampledRelation() ~~visitLateral()~~ visitValues() or visitRelation()

Issue Analytics

State:
Created 2 years ago
Comments:7 (7 by maintainers)

Top GitHub Comments

1reaction

pranjalsshcommented, Oct 11, 2021

@gggrace14 I’m unable to edit this issue. Here’s something we can add:

We do not support subqueries within WHERE clause. E.g.:

SELECT * FROM t1 WHERE a = (SELECT max(b) from t2 WHERE t1.ds = t2.ds)

For this, we need to implement visit for all types of expressions. These can also be implemented via joins and we do not have enough usecases to support these type of queries.

0reactions

gggrace14commented, Oct 11, 2021

Hi @pranjalssh , can you add a short description to this Issue of your findings of query in predicate not being support as well as our current thought? That will complete this Issue and reflect our up-to-date decision. https://github.com/prestodb/presto/blob/14126619596162e18ec8099f4f911f9e5836880b/presto-parser/src/main/antlr4/com/facebook/presto/sql/parser/SqlBase.g4#L345-L348

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