289 lines
9.7 KiB
Plaintext
289 lines
9.7 KiB
Plaintext
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> -- | The AST for SQL queries
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> module Language.SQL.SimpleSQL.Syntax
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> (-- * Scalar expressions
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> ScalarExpr(..)
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> ,Name(..)
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> ,TypeName(..)
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> ,Duplicates(..)
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> ,OrderField(..)
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> ,Direction(..)
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> ,NullsOrder(..)
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> ,InThing(..)
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> ,SubQueryExprType(..)
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> ,Frame(..)
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> ,FrameRows(..)
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> ,FramePos(..)
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> -- * Query expressions
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> ,QueryExpr(..)
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> ,makeSelect
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> ,CombineOp(..)
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> ,Corresponding(..)
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> ,Alias(..)
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> ,GroupingExpr(..)
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> -- ** From
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> ,TableRef(..)
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> ,JoinType(..)
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> ,JoinCondition(..)
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> ) where
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> -- | Represents a scalar expression
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> data ScalarExpr
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> = -- | a numeric literal optional decimal point, e+-
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> -- integral exponent, e.g
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> --
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> -- * 10
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> --
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> -- * 10.
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> --
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> -- * .1
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> --
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> -- * 10.1
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> --
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> -- * 1e5
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> --
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> -- * 12.34e-6
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> NumLit String
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> -- | string literal, currently only basic strings between
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> -- single quotes without escapes (no single quotes in strings
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> -- then)
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> | StringLit String
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> -- | text of interval literal, units of interval precision,
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> -- e.g. interval 3 days (3)
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> | IntervalLit
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> {ilLiteral :: String -- ^ literal text
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> ,ilUnits :: String -- ^ units
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> ,ilPrecision :: Maybe Int -- ^ precision
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> }
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> -- | identifier without dots
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> | Iden Name
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> -- | star, as in select *, t.*, count(*)
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> | Star
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> -- | function application (anything that looks like c style
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> -- function application syntactically)
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> | App Name [ScalarExpr]
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> -- | aggregate application, which adds distinct or all, and
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> -- order by, to regular function application
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> | AggregateApp
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> {aggName :: Name -- ^ aggregate function name
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> ,aggDistinct :: Maybe Duplicates -- ^ distinct
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> ,aggArgs :: [ScalarExpr]-- ^ args
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> ,aggOrderBy :: [OrderField] -- ^ order by
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> }
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> -- | window application, which adds over (partition by a order
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> -- by b) to regular function application. Explicit frames are
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> -- not currently supported
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> | WindowApp
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> {wnName :: Name -- ^ window function name
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> ,wnArgs :: [ScalarExpr] -- ^ args
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> ,wnPartition :: [ScalarExpr] -- ^ partition by
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> ,wnOrderBy :: [OrderField] -- ^ order by
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> ,wnFrame :: Maybe Frame -- ^ frame clause
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> }
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> -- | Infix binary operators. This is used for symbol operators
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> -- (a + b), keyword operators (a and b) and multiple keyword
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> -- operators (a is similar to b)
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> | BinOp ScalarExpr Name ScalarExpr
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> -- | Prefix unary operators. This is used for symbol
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> -- operators, keyword operators and multiple keyword operators
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> | PrefixOp Name ScalarExpr
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> -- | Postfix unary operators. This is used for symbol
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> -- operators, keyword operators and multiple keyword operators
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> | PostfixOp Name ScalarExpr
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> -- | Used for ternary, mixfix and other non orthodox
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> -- operators, including the function looking calls which use
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> -- keywords instead of commas to separate the arguments,
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> -- e.g. substring(t from 1 to 5)
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> | SpecialOp Name [ScalarExpr]
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> -- | case expression. both flavours supported. Multiple
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> -- condition when branches not currently supported (case when
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> -- a=4,b=5 then x end)
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> | Case
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> {caseTest :: Maybe ScalarExpr -- ^ test value
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> ,caseWhens :: [([ScalarExpr],ScalarExpr)] -- ^ when branches
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> ,caseElse :: Maybe ScalarExpr -- ^ else value
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> }
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> | Parens ScalarExpr
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> -- | cast(a as typename)
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> | Cast ScalarExpr TypeName
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> -- | prefix 'typed literal', e.g. int '42'
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> | TypedLit TypeName String
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> -- | exists, all, any, some subqueries
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> | SubQueryExpr SubQueryExprType QueryExpr
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> -- | in list literal and in subquery, if the bool is false it
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> -- means not in was used ('a not in (1,2)')
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> | In Bool ScalarExpr InThing
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> deriving (Eq,Show,Read)
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> -- | Represents an identifier name, which can be quoted or unquoted
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> data Name = Name String
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> | QName String
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> deriving (Eq,Show,Read)
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> -- | Represents a type name, used in casts.
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> data TypeName = TypeName String
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> | PrecTypeName String Int
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> | Prec2TypeName String Int Int
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> deriving (Eq,Show,Read)
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> -- | Used for 'expr in (scalar expression list)', and 'expr in
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> -- (subquery)' syntax
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> data InThing = InList [ScalarExpr]
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> | InQueryExpr QueryExpr
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> deriving (Eq,Show,Read)
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> -- | A subquery in a scalar expression
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> data SubQueryExprType
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> = -- | exists (query expr)
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> SqExists
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> -- | a scalar subquery
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> | SqSq
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> -- | all (query expr)
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> | SqAll
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> -- | some (query expr)
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> | SqSome
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> -- | any (query expr)
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> | SqAny
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> deriving (Eq,Show,Read)
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> data OrderField = OrderField ScalarExpr Direction NullsOrder
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> deriving (Eq,Show,Read)
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> data NullsOrder = NullsOrderDefault
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> | NullsFirst
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> | NullsLast
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> deriving (Eq,Show,Read)
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> -- | Represents the frame clause of a window
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> -- this can be [range | rows] frame_start
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> -- or [range | rows] between frame_start and frame_end
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> data Frame = FrameFrom FrameRows FramePos
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> | FrameBetween FrameRows FramePos FramePos
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> deriving (Eq,Show,Read)
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> -- | Represents whether a window frame clause is over rows or ranges
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> data FrameRows = FrameRows | FrameRange
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> deriving (Eq,Show,Read)
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> -- | represents the start or end of a frame
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> data FramePos = UnboundedPreceding
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> | Preceding ScalarExpr
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> | Current
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> | Following ScalarExpr
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> | UnboundedFollowing
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> deriving (Eq,Show,Read)
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> -- | Represents a query expression, which can be:
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> --
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> -- * a regular select;
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> --
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> -- * a set operator (union, except, intersect);
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> --
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> -- * a common table expression (with);
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> --
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> -- * a values expression (not yet supported);
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> --
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> -- * or the table syntax - 'table t', shorthand for 'select * from
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> -- t' (not yet supported).
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> data QueryExpr
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> = Select
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> {qeDuplicates :: Duplicates
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> ,qeSelectList :: [(Maybe Name,ScalarExpr)]
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> -- ^ the column aliases and the expressions
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> ,qeFrom :: [TableRef]
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> ,qeWhere :: Maybe ScalarExpr
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> ,qeGroupBy :: [GroupingExpr]
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> ,qeHaving :: Maybe ScalarExpr
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> ,qeOrderBy :: [OrderField]
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> ,qeOffset :: Maybe ScalarExpr
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> ,qeFetch :: Maybe ScalarExpr
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> }
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> | CombineQueryExpr
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> {qe0 :: QueryExpr
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> ,qeCombOp :: CombineOp
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> ,qeDuplicates :: Duplicates
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> ,qeCorresponding :: Corresponding
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> ,qe1 :: QueryExpr
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> }
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> | With
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> {qeWithRecursive :: Bool
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> ,qeViews :: [(Alias,QueryExpr)]
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> ,qeQueryExpression :: QueryExpr}
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> | Values [[ScalarExpr]]
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> | Table Name
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> deriving (Eq,Show,Read)
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TODO: add queryexpr parens to deal with e.g.
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(select 1 union select 2) union select 3
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I'm not sure if this is valid syntax or not.
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> -- | helper/'default' value for query exprs to make creating query
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> -- expr values a little easier
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> makeSelect :: QueryExpr
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> makeSelect = Select {qeDuplicates = All
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> ,qeSelectList = []
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> ,qeFrom = []
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> ,qeWhere = Nothing
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> ,qeGroupBy = []
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> ,qeHaving = Nothing
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> ,qeOrderBy = []
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> ,qeOffset = Nothing
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> ,qeFetch = Nothing}
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> -- | represents the Distinct or All keywords, which can be used
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> -- before a select list, in an aggregate/window function
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> -- application, or in a query expression set operator
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> data Duplicates = Distinct | All deriving (Eq,Show,Read)
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> -- | The direction for a column in order by.
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> data Direction = Asc | Desc deriving (Eq,Show,Read)
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> -- | Query expression set operators
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> data CombineOp = Union | Except | Intersect deriving (Eq,Show,Read)
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> -- | Corresponding, an option for the set operators
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> data Corresponding = Corresponding | Respectively deriving (Eq,Show,Read)
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> data GroupingExpr
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> = GroupingParens [GroupingExpr]
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> | Cube [GroupingExpr]
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> | Rollup [GroupingExpr]
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> | GroupingSets [GroupingExpr]
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> | SimpleGroup ScalarExpr
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> deriving (Eq,Show,Read)
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> -- | Represents a entry in the csv of tables in the from clause.
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> data TableRef = -- | from t
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> TRSimple Name
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> -- | from a join b
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> | TRJoin TableRef JoinType TableRef (Maybe JoinCondition)
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> -- | from (a)
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> | TRParens TableRef
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> -- | from a as b(c,d)
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> | TRAlias TableRef Alias
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> -- | from (query expr)
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> | TRQueryExpr QueryExpr
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> -- | from function(args)
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> | TRFunction Name [ScalarExpr]
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> -- | from lateral t
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> | TRLateral TableRef
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> deriving (Eq,Show,Read)
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> -- | Represents an alias for a table valued expression, used in with
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> -- queries and in from alias, e.g. select a from t u, select a from t u(b),
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> -- with a(c) as select 1, select * from a;
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> data Alias = Alias Name (Maybe [Name])
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> deriving (Eq,Show,Read)
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TODO: add function table ref
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> -- | The type of a join
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> data JoinType = JInner | JLeft | JRight | JFull | JCross
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> deriving (Eq,Show,Read)
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> -- | The join condition.
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> data JoinCondition = JoinOn ScalarExpr -- ^ on expr
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> | JoinUsing [Name] -- ^ using (column list)
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> | JoinNatural -- ^ natural join was used
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> deriving (Eq,Show,Read)
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