query.ebnf(select): sync with query.pest

Summarize the changes

• query.ebnf: add scan diagram
• query.ebnf(select): sync with query.pest
• query.ebnf(update): sync with query.pest
• query.ebnf: replace with "query" where needed

В продолжение обсуждения в docs#244 (closed)

Должен быть влит после !492 (merged)

Предлагаемые изменения

1. Добавить диаграмму scan
2. Изменить определение диаграммы select
3. Изменить определение диаграммы update
4. Переименовать диаграмму cte -> query и заменить select на query в диаграммах — согласно определениям из query.pest

Диаграмма `query.svg`

Диаграмма `select.svg`

Диаграмма `scan.svg`

Диаграмма `update.svg`

Описание

В query.pest есть три выражения SELECT:

1. SelectFull:

   SelectFull = {
       (^"with" ~ Cte ~ ("," ~ Cte)*)?
       ~ SelectWithOptionalContinuation
   }

   Подвыражения

   Cte, CteColumn:

   Cte = { Identifier ~ ("(" ~ CteColumn ~ ("," ~ CteColumn)* ~ ")")? ~ ^"as"
           ~ "(" ~ (SelectWithOptionalContinuation | Values) ~ ")" }
   CteColumn = @{ Identifier }

2. SelectWithOptionalContinuation – сокращу до SelectWOC:

   SelectWithOptionalContinuation = { Select ~ (SelectOp ~ Select)* }
   SelectOp = _{ UnionAllOp | ExceptOp | UnionOp }
       UnionOp = { ^"union" }
       ExceptOp = { (^"except" ~ ^"distinct") | ^"except" }
       UnionAllOp = { ^"union" ~ ^"all" }

3. Select:

   Select = {
       ^"select" ~ Projection ~ ^"from" ~ Scan ~
       Join* ~ WhereClause? ~
       (^"group" ~ ^"by" ~ GroupBy)? ~
       (^"having" ~ Having)? ~
       (^"order" ~ ^"by" ~ OrderBy)?
   }

   Подвыражения

   Projection, WhereClause, Scan, Join, GroupBy, Having, OrderBy:

   Projection = { Distinct? ~ ProjectionElement ~ ("," ~ ProjectionElement)* }
       ProjectionElement = _{ Asterisk | Column }
       Column = { Expr ~ ((^"as")? ~ Identifier)? }
       Asterisk = { (Identifier ~ ".")? ~ "*" }
   WhereClause = _{ ^"where" ~ Selection }
   Selection = { Expr }
   Scan = { (ScanCteOrTable| SubQuery) ~ ((^"as")? ~ Identifier)? }
   Join = { JoinKind? ~ ^"join" ~ Scan ~ ^"on" ~ Expr }
       JoinKind = _{ ( InnerJoinKind | LeftJoinKind ) }
           InnerJoinKind = { ^"inner" }
           LeftJoinKind = { ^"left" ~ (^"outer")? }
   GroupBy = { Expr ~ ("," ~ Expr)* }
   Having = { Expr }
   OrderBy = { OrderByElement ~ ("," ~ OrderByElement)* }
       OrderByElement = { Expr ~ OrderFlag? }
       OrderFlag = _{ Asc | Desc }
           Asc = { ^"asc" }
           Desc = { ^"desc" }
   SubQuery = { "(" ~ (SelectFull | Values) ~ ")" }

Использование

1. Select:

   • INSERT — Insert — исправлено в !492 (merged)
   • SELECT, после ('UNION' 'ALL'? | 'EXCEPT' 'DISTINCT'?) — SelectWOC

2. SelectWOC:

   • WITH и CTE — SelectFull, Cte

3. SelectFull — все остальные диаграммы

Ensure that

• New code is covered by unit and integration tests.
• Related issues would be automatically closed with gitlab's closing pattern (Closes #1, #2).
• Public modules are documented (check the rendered version with cargo doc --open).
• (if PEST grammar is changed) EBNF grammar reflects these changes (check the result with railroad diagram generator.

Next steps

• Cherry-pick to: none / 24.2 / 24.3
• Update sbroad submodule in picodata/picodata.
• (if EBNF grammar is changed) create a follow-up issue in picodata/docs — docs!516 (merged)