ast: reset JoinLevel at the beginning of TableRefsClause.Restore#1036
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Hexilee wants to merge 2 commits intopingcap:masterfrom
Open
ast: reset JoinLevel at the beginning of TableRefsClause.Restore#1036Hexilee wants to merge 2 commits intopingcap:masterfrom
Hexilee wants to merge 2 commits intopingcap:masterfrom
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Signed-off-by: hexilee <[email protected]>
Contributor
|
The culprit is actually the diff --git a/ast/dml.go b/ast/dml.go
index f6e4a1d..ac33cf8 100644
--- a/ast/dml.go
+++ b/ast/dml.go
@@ -91,12 +91,15 @@ func (n *Join) Restore(ctx *format.RestoreCtx) error {
ctx.WritePlain("(")
defer ctx.WritePlain(")")
}
- ctx.JoinLevel++
+ if n.Right != nil {
+ ctx.JoinLevel++
+ }
if err := n.Left.Restore(ctx); err != nil {
return errors.Annotate(err, "An error occurred while restore Join.Left")
}
- ctx.JoinLevel--
- if n.Right == nil {
+ if n.Right != nil {
+ ctx.JoinLevel--
+ } else {
return nil
}
if n.NaturalJoin {also move the test case to |
Author
|
I don't think so. The following example also causes a syntax error in mysql. -- origin
SELECT * FROM (SELECT * FROM (SELECT * FROM `t1`) AS `tmp`) AS `tmp`, t-- restored
SELECT * FROM (SELECT * FROM ((SELECT * FROM (`t1`)) AS `tmp`)) AS `tmp`, tThe culprit is the |
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Signed-off-by: hexilee [email protected]
What problem does this PR solve?
Currently,
format.RestoreCtx.JoinLeveldoes not work well in the multi-level subquery.If you parse the following SQL and restore it, you will get unnecessary pairs of parentheses in the inner subquery.
Unnecessary parentheses can be ignored by tidb. However, in mysql, it will cause a syntax error.
What is changed and how it works?
This PR resets
JoinLevelat the beginning ofTableRefsClause.Restore, thenJoinLevelwill never affect subqueries.Check List
Tests
Code changes