datafusion-sqlparse/tests/sqlparser_snowflake.rs
Nickolay Ponomarev ad72cda6b0 [snowflake] Support specifying an alias after FROM (table_factor)
Snowflake diverges from the standard and from most of the other
implementations by allowing extra parentheses not only around a join,
but around lone table names (e.g. `FROM (mytable [AS alias])`) and
around derived tables (e.g. `FROM ((SELECT ...)  [AS alias])`) as well.

Initially this was implemented in https://github.com/ballista-compute/sqlparser-rs/issues/154
by (ab)using `TableFactor::NestedJoin` to represent anything nested in
extra set of parens.

Afterwards we learned in https://github.com/ballista-compute/sqlparser-rs/issues/223
that in cases of such extraneous nesting Snowflake allows specifying the
alias both inside and outside parens, but not both - consider:

    FROM (table_factor AS inner_alias) AS outer_alias

We've considered implementing this by changing `TableFactor::NestedJoin`
to a `TableFactor::Nested { inner: TableWithJoins, alias:
Option<TableAlias> }`, but that seemed too generic, as no known dialect
supports duplicate aliases, as shown above, nor naming nested joins
`(foo NATURAL JOIN bar) alias`. So we decided on making a smaller change
(with no modifications to the AST), that is also more appropriate to the
contributors to the Snowflake dialect:


1) Revert #154 by rejecting `FROM (table or derived table)` in most dialects.

2) For `dialect_of!(self is SnowflakeDialect | GenericDialect)` parse
and strip the extraneous parentheses, e.g.

   `(mytable) AS alias` -> `(mytable AS alias)`


Co-authored-by: Eyal Leshem <eyal@satoricyber.com>
2020-10-13 09:51:02 +03:00

157 lines
5 KiB
Rust

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#![warn(clippy::all)]
//! Test SQL syntax specific to Snowflake. The parser based on the
//! generic dialect is also tested (on the inputs it can handle).
#[macro_use]
mod test_utils;
use test_utils::*;
use sqlparser::ast::*;
use sqlparser::dialect::{GenericDialect, SnowflakeDialect};
use sqlparser::parser::ParserError;
use sqlparser::tokenizer::*;
#[test]
fn test_snowflake_create_table() {
let sql = "CREATE TABLE _my_$table (am00unt number)";
match snowflake_and_generic().verified_stmt(sql) {
Statement::CreateTable { name, .. } => {
assert_eq!("_my_$table", name.to_string());
}
_ => unreachable!(),
}
}
#[test]
fn test_snowflake_single_line_tokenize() {
let sql = "CREATE TABLE# this is a comment \ntable_1";
let dialect = SnowflakeDialect {};
let mut tokenizer = Tokenizer::new(&dialect, &sql);
let tokens = tokenizer.tokenize().unwrap();
let expected = vec![
Token::make_keyword("CREATE"),
Token::Whitespace(Whitespace::Space),
Token::make_keyword("TABLE"),
Token::Whitespace(Whitespace::SingleLineComment {
prefix: "#".to_string(),
comment: " this is a comment \n".to_string(),
}),
Token::make_word("table_1", None),
];
assert_eq!(expected, tokens);
let sql = "CREATE TABLE// this is a comment \ntable_1";
let mut tokenizer = Tokenizer::new(&dialect, &sql);
let tokens = tokenizer.tokenize().unwrap();
let expected = vec![
Token::make_keyword("CREATE"),
Token::Whitespace(Whitespace::Space),
Token::make_keyword("TABLE"),
Token::Whitespace(Whitespace::SingleLineComment {
prefix: "//".to_string(),
comment: " this is a comment \n".to_string(),
}),
Token::make_word("table_1", None),
];
assert_eq!(expected, tokens);
}
#[test]
fn test_sf_derived_table_in_parenthesis() {
// Nesting a subquery in an extra set of parentheses is non-standard,
// but supported in Snowflake SQL
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM ((SELECT 1) AS t)",
"SELECT * FROM (SELECT 1) AS t",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (((SELECT 1) AS t))",
"SELECT * FROM (SELECT 1) AS t",
);
}
#[test]
fn test_single_table_in_parenthesis() {
// Parenthesized table names are non-standard, but supported in Snowflake SQL
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN (b))",
"SELECT * FROM (a NATURAL JOIN b)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN ((b)))",
"SELECT * FROM (a NATURAL JOIN b)",
);
}
#[test]
fn test_single_table_in_parenthesis_with_alias() {
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN (b) c )",
"SELECT * FROM (a NATURAL JOIN b AS c)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN ((b)) c )",
"SELECT * FROM (a NATURAL JOIN b AS c)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN ( (b) c ) )",
"SELECT * FROM (a NATURAL JOIN b AS c)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a NATURAL JOIN ( (b) as c ) )",
"SELECT * FROM (a NATURAL JOIN b AS c)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a alias1 NATURAL JOIN ( (b) c ) )",
"SELECT * FROM (a AS alias1 NATURAL JOIN b AS c)",
);
snowflake_and_generic().one_statement_parses_to(
"SELECT * FROM (a as alias1 NATURAL JOIN ( (b) as c ) )",
"SELECT * FROM (a AS alias1 NATURAL JOIN b AS c)",
);
let res = snowflake_and_generic().parse_sql_statements("SELECT * FROM (a NATURAL JOIN b) c");
assert_eq!(
ParserError::ParserError("Expected end of statement, found: c".to_string()),
res.unwrap_err()
);
let res = snowflake().parse_sql_statements("SELECT * FROM (a b) c");
assert_eq!(
ParserError::ParserError("duplicate alias b".to_string()),
res.unwrap_err()
);
}
fn snowflake() -> TestedDialects {
TestedDialects {
dialects: vec![Box::new(SnowflakeDialect {})],
}
}
fn snowflake_and_generic() -> TestedDialects {
TestedDialects {
dialects: vec![Box::new(SnowflakeDialect {}), Box::new(GenericDialect {})],
}
}