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support select dummy from dual

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This commit is contained in:
obdev
2023-07-21 10:18:46 +00:00
committed by ob-robot
parent 52d353303f
commit 3ba3e1b1ee
2 changed files with 63 additions and 17 deletions
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49
src/sql/resolver/dml/ob_select_resolver.cpp
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@ -2069,6 +2069,12 @@ int ObSelectResolver::resolve_field_list(const ParseNode &node)
LOG_WARN("alias name too long", K(ret), K(select_item.alias_name_));
}
}
} else if (is_oracle_mode() && 0 == select_stmt->get_table_size()
&& 0 == select_item.expr_name_.case_compare("DUMMY")) {
const char *ptr_name = "DUMMY";
ObString string_name(ptr_name);
select_item.alias_name_ = string_name;
select_item.is_real_alias_ = true;
} else {
if (params_.is_prepare_protocol_
|| !session_info_->get_local_ob_enable_plan_cache()
@ -2607,26 +2613,39 @@ int ObSelectResolver::resolve_star(const ParseNode *node)
// (select * from dual) is legitimate for oracle ==> output: X
ObConstRawExpr *c_expr = NULL;
const char *ptr_value = "X";
const char *ptr_name = "D";
const char *ptr_name = "DUMMY";
ObString string_value(1, ptr_value);
ObString string_name(1, ptr_name);
ObString string_name(ptr_name);
if (select_stmt->has_group_by() || has_group_by_clause()) {
ret = OB_ERR_WRONG_FIELD_WITH_GROUP;
LOG_DEBUG("not a GROUP BY expression", K(ret));
} else if (OB_FAIL(params_.expr_factory_->create_raw_expr(T_VARCHAR, c_expr))) {
LOG_WARN("fail to create const raw c_expr", K(ret));
} else if (OB_FAIL(ObRawExprUtils::build_const_string_expr(*params_.expr_factory_,
ObCharType,ptr_value, session_info_->get_nls_collation(), c_expr))){
LOG_WARN("fail to create const string c_expr", K(ret));
} else {
ObObj obj;
obj.set_string(ObVarcharType, string_value);
obj.set_collation_type(CS_TYPE_UTF8MB4_BIN);
c_expr->set_value(obj);
select_item.expr_ = c_expr;
select_item.expr_name_ = string_name;
select_item.alias_name_ = string_name;
select_item.is_real_alias_ = true;
if (OB_FAIL(select_stmt->add_select_item(select_item))) {
LOG_WARN("failed to add select item", K(ret));
} else {/*do nothing*/}
ObSysFunRawExpr *cast_expr = NULL;
ObExprResType res_type;
res_type.set_type(ObVarcharType);
res_type.set_length(1);
res_type.set_length_semantics(LS_BYTE);
res_type.set_collation_level(CS_LEVEL_IMPLICIT);
res_type.set_collation_type(session_info_->get_nls_collation());
if (OB_FAIL(ObRawExprUtils::create_cast_expr(*params_.expr_factory_, c_expr,
res_type, cast_expr, session_info_))) {
LOG_WARN("create cast expr for dummy failed", K(ret));
} else if (OB_FAIL(cast_expr->clear_flag(IS_INNER_ADDED_EXPR))) {
LOG_WARN("failed to clear flag for cast expr", K(ret));
} else if (OB_FAIL(cast_expr->formalize(session_info_))) {
LOG_WARN("failed to formalize cast expr", K(ret));
} else {
select_item.expr_ = cast_expr;
select_item.expr_name_ = string_name;
select_item.alias_name_ = string_name;
select_item.is_real_alias_ = true;
if (OB_FAIL(select_stmt->add_select_item(select_item))) {
LOG_WARN("failed to add select item", K(ret));
} else {/*do nothing*/}
}
}
}
if (OB_SUCC(ret) && !is_oracle_mode() && !params_.has_cte_param_list_) {