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fix bug on pushing down groupby into union with empty table and const group expr

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AA-tuliwei-BB 2024-11-28 03:45:10 +00:00 committed by ob-robot
parent 95776db7b0
commit 79eba2e1e9
1 changed files with 20 additions and 0 deletions
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20
src/sql/rewrite/ob_transform_groupby_pushdown.cpp
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@ -346,6 +346,26 @@ int ObTransformGroupByPushdown::check_aggr_exprs_valid(ObSelectStmt &stmt,
}
}
}
// dima-2024112700105312838
// For empty table t1, "select count(*) from t1" is not equal to "select count(*) t1 group by 'a'".
// Now the transform rule only pushdown column expr in group expr, so we cant't transform query that
// has all expr not containing column in its group scope.
if (OB_SUCC(ret) && is_valid && 0 != stmt.get_group_expr_size()) {
bool contain_column = false;
ObIArray<ObRawExpr *> &group_exprs = stmt.get_group_exprs();
for (int64_t i = 0; OB_SUCC(ret) && !contain_column && i < group_exprs.count(); ++i) {
ObRawExpr *group_expr = group_exprs.at(i);
if (OB_ISNULL(group_expr)) {
ret = OB_ERR_UNEXPECTED;
LOG_WARN("unexpected null group expr", K(ret));
} else if (group_expr->has_flag(CNT_COLUMN)) {
contain_column = true;
}
}
if (!contain_column) {
is_valid = false;
}
}
return ret;
}