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Allow SQL standard FETCH without OFFSET

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This commit is contained in:
Alexey Milovidov 2023-06-22 22:50:09 +02:00
parent aa2b8aa893
commit 289d9849d4
3 changed files with 119 additions and 42 deletions
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94
src/Parsers/ParserSelectQuery.cpp
View File

@ -292,6 +292,9 @@ bool ParserSelectQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
/// This is needed for TOP expression, because it can also use WITH TIES.
bool limit_with_ties_occured = false;
bool has_offset_clause = false;
bool offset_clause_has_sql_standard_row_or_rows = false; /// OFFSET offset_row_count {ROW | ROWS}
/// LIMIT length | LIMIT offset, length | LIMIT count BY expr-list | LIMIT offset, length BY expr-list
if (s_limit.ignore(pos, expected))
{
@ -316,6 +319,8 @@ bool ParserSelectQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
if (!exp_elem.parse(pos, limit_offset, expected))
return false;
has_offset_clause = true;
}
else if (s_with_ties.ignore(pos, expected))
{
@ -351,60 +356,65 @@ bool ParserSelectQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
}
else if (s_offset.ignore(pos, expected))
{
/// OFFSET offset_row_count {ROW | ROWS} FETCH {FIRST | NEXT} fetch_row_count {ROW | ROWS} {ONLY | WITH TIES}
bool offset_with_fetch_maybe = false;
/// OFFSET without LIMIT
has_offset_clause = true;
if (!exp_elem.parse(pos, limit_offset, expected))
return false;
/// SQL standard OFFSET N ROW[S] ...
if (s_row.ignore(pos, expected))
offset_clause_has_sql_standard_row_or_rows = true;
if (s_rows.ignore(pos, expected))
{
if (offset_clause_has_sql_standard_row_or_rows)
throw Exception(ErrorCodes::ROW_AND_ROWS_TOGETHER, "Can not use ROW and ROWS together");
offset_clause_has_sql_standard_row_or_rows = true;
}
}
/// SQL standard FETCH (either following SQL standard OFFSET or following ORDER BY)
if ((!has_offset_clause || offset_clause_has_sql_standard_row_or_rows)
&& s_fetch.ignore(pos, expected))
{
/// FETCH clause must exist with "ORDER BY"
if (!order_expression_list)
throw Exception(ErrorCodes::OFFSET_FETCH_WITHOUT_ORDER_BY, "Can not use OFFSET FETCH clause without ORDER BY");
if (s_first.ignore(pos, expected))
{
if (s_next.ignore(pos, expected))
throw Exception(ErrorCodes::FIRST_AND_NEXT_TOGETHER, "Can not use FIRST and NEXT together");
}
else if (!s_next.ignore(pos, expected))
return false;
if (!exp_elem.parse(pos, limit_length, expected))
return false;
if (s_row.ignore(pos, expected))
{
if (s_rows.ignore(pos, expected))
throw Exception(ErrorCodes::ROW_AND_ROWS_TOGETHER, "Can not use ROW and ROWS together");
offset_with_fetch_maybe = true;
}
else if (s_rows.ignore(pos, expected))
else if (!s_rows.ignore(pos, expected))
return false;
if (s_with_ties.ignore(pos, expected))
{
offset_with_fetch_maybe = true;
select_query->limit_with_ties = true;
}
if (offset_with_fetch_maybe && s_fetch.ignore(pos, expected))
else if (s_only.ignore(pos, expected))
{
/// OFFSET FETCH clause must exists with "ORDER BY"
if (!order_expression_list)
throw Exception(ErrorCodes::OFFSET_FETCH_WITHOUT_ORDER_BY, "Can not use OFFSET FETCH clause without ORDER BY");
if (s_first.ignore(pos, expected))
{
if (s_next.ignore(pos, expected))
throw Exception(ErrorCodes::FIRST_AND_NEXT_TOGETHER, "Can not use FIRST and NEXT together");
}
else if (!s_next.ignore(pos, expected))
return false;
if (!exp_elem.parse(pos, limit_length, expected))
return false;
if (s_row.ignore(pos, expected))
{
if (s_rows.ignore(pos, expected))
throw Exception(ErrorCodes::ROW_AND_ROWS_TOGETHER, "Can not use ROW and ROWS together");
}
else if (!s_rows.ignore(pos, expected))
return false;
if (s_with_ties.ignore(pos, expected))
{
select_query->limit_with_ties = true;
}
else if (s_only.ignore(pos, expected))
{
select_query->limit_with_ties = false;
}
else
{
return false;
}
select_query->limit_with_ties = false;
}
else
{
return false;
}
}

36
tests/queries/0_stateless/02790_sql_standard_fetch.reference Normal file
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@ -0,0 +1,36 @@
┌─id─┬─name──┬─department─┬─salary─┐
│ 25 │ Frank │ it │ 120 │
│ 23 │ Henry │ it │ 104 │
│ 24 │ Irene │ it │ 104 │
│ 33 │ Alice │ sales │ 100 │
│ 32 │ Dave │ sales │ 96 │
└────┴───────┴────────────┴────────┘
┌─id─┬─name──┬─department─┬─salary─┐
│ 25 │ Frank │ it │ 120 │
│ 23 │ Henry │ it │ 104 │
│ 24 │ Irene │ it │ 104 │
│ 33 │ Alice │ sales │ 100 │
│ 32 │ Dave │ sales │ 96 │
└────┴───────┴────────────┴────────┘
┌─id─┬─name──┬─department─┬─salary─┐
│ 25 │ Frank │ it │ 120 │
│ 23 │ Henry │ it │ 104 │
│ 24 │ Irene │ it │ 104 │
│ 33 │ Alice │ sales │ 100 │
│ 31 │ Cindy │ sales │ 96 │
│ 32 │ Dave │ sales │ 96 │
└────┴───────┴────────────┴────────┘
┌─id─┬─name──┬─department─┬─salary─┐
│ 33 │ Alice │ sales │ 100 │
│ 31 │ Cindy │ sales │ 96 │
│ 32 │ Dave │ sales │ 96 │
│ 22 │ Grace │ it │ 90 │
│ 21 │ Emma │ it │ 84 │
└────┴───────┴────────────┴────────┘
┌─id─┬─name──┬─department─┬─salary─┐
│ 33 │ Alice │ sales │ 100 │
│ 31 │ Cindy │ sales │ 96 │
│ 32 │ Dave │ sales │ 96 │
│ 22 │ Grace │ it │ 90 │
│ 21 │ Emma │ it │ 84 │
└────┴───────┴────────────┴────────┘

31
tests/queries/0_stateless/02790_sql_standard_fetch.sql Normal file
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@ -0,0 +1,31 @@
# https://antonz.org/sql-fetch/
CREATE TEMPORARY TABLE employees (id UInt64, name String, department String, salary UInt64);
INSERT INTO employees VALUES (23, 'Henry', 'it', 104), (24, 'Irene', 'it', 104), (25, 'Frank', 'it', 120), (31, 'Cindy', 'sales', 96), (33, 'Alice', 'sales', 100), (32, 'Dave', 'sales', 96), (22, 'Grace', 'it', 90), (21, 'Emma', 'it', '84');
select * from employees
order by salary desc
limit 5
format PrettyCompactNoEscapes;
select * from employees
order by salary desc
fetch first 5 rows only
format PrettyCompactNoEscapes;
select * from employees
order by salary desc
fetch first 5 rows with ties
format PrettyCompactNoEscapes;
select * from employees
order by salary desc
offset 3 rows
fetch next 5 rows only
format PrettyCompactNoEscapes;
select * from employees
order by salary desc
offset 3 rows
fetch first 5 rows only
format PrettyCompactNoEscapes;