Copyright	(c) Eitan Chatav 2019
Maintainer	[email protected]
Stability	experimental
Safe Haskell	None
Language	Haskell2010

Squeal.PostgreSQL.Query.Table

Contents

Table Expression
Grouping

Description

intermediate table expressions

Synopsis

data TableExpression (grp :: Grouping) (lat :: FromType) (with :: FromType) (db :: SchemasType) (params :: [NullType]) (from :: FromType) = TableExpression {
- fromClause :: FromClause lat with db params from
- whereClause :: [Condition Ungrouped lat with db params from]
- groupByClause :: GroupByClause grp from
- havingClause :: HavingClause grp lat with db params from
- orderByClause :: [SortExpression grp lat with db params from]
- limitClause :: [Word64]
- offsetClause :: [Word64]
}
from :: FromClause lat with db params from -> TableExpression Ungrouped lat with db params from
where_ :: Condition Ungrouped lat with db params from -> TableExpression grp lat with db params from -> TableExpression grp lat with db params from
groupBy :: SListI bys => NP (By from) bys -> TableExpression Ungrouped lat with db params from -> TableExpression (Grouped bys) lat with db params from
having :: Condition (Grouped bys) lat with db params from -> TableExpression (Grouped bys) lat with db params from -> TableExpression (Grouped bys) lat with db params from
limit :: Word64 -> TableExpression grp lat with db params from -> TableExpression grp lat with db params from
offset :: Word64 -> TableExpression grp lat with db params from -> TableExpression grp lat with db params from
data By (from :: FromType) (by :: (Symbol, Symbol)) where
- By1 :: (HasUnique table from columns, Has column columns ty) => Alias column -> By from '(table, column)
- By2 :: (Has table from columns, Has column columns ty) => Alias table -> Alias column -> By from '(table, column)
newtype GroupByClause grp from = UnsafeGroupByClause {
- renderGroupByClause :: ByteString
}
data HavingClause grp lat with db params from where
- NoHaving :: HavingClause Ungrouped lat with db params from
- Having :: [Condition (Grouped bys) lat with db params from] -> HavingClause (Grouped bys) lat with db params from

Table Expression

data TableExpression (grp :: Grouping) (lat :: FromType) (with :: FromType) (db :: SchemasType) (params :: [NullType]) (from :: FromType) Source #

A TableExpression computes a table. The table expression contains a fromClause that is optionally followed by a whereClause, groupByClause, havingClause, orderByClause, limitClause and offsetClauses. Trivial table expressions simply refer to a table on disk, a so-called base table, but more complex expressions can be used to modify or combine base tables in various ways.

Constructors

TableExpression

Fields

fromClause :: FromClause lat with db params from
A table reference that can be a table name, or a derived table such as a subquery, a JOIN construct, or complex combinations of these.
whereClause :: [Condition Ungrouped lat with db params from]
optional search coditions, combined with .&&. After the processing of the fromClause is done, each row of the derived virtual table is checked against the search condition. If the result of the condition is true, the row is kept in the output table, otherwise it is discarded. The search condition typically references at least one column of the table generated in the fromClause; this is not required, but otherwise the WHERE clause will be fairly useless.
groupByClause :: GroupByClause grp from
The groupByClause is used to group together those rows in a table that have the same values in all the columns listed. The order in which the columns are listed does not matter. The effect is to combine each set of rows having common values into one group row that represents all rows in the group. This is done to eliminate redundancy in the output and/or compute aggregates that apply to these groups.
havingClause :: HavingClause grp lat with db params from
If a table has been grouped using groupBy, but only certain groups are of interest, the havingClause can be used, much like a whereClause, to eliminate groups from the result. Expressions in the havingClause can refer both to grouped expressions and to ungrouped expressions (which necessarily involve an aggregate function).
orderByClause :: [SortExpression grp lat with db params from]
The orderByClause is for optional sorting. When more than one SortExpression is specified, the later (right) values are used to sort rows that are equal according to the earlier (left) values.
limitClause :: [Word64]
The limitClause is combined with min to give a limit count if nonempty. If a limit count is given, no more than that many rows will be returned (but possibly fewer, if the query itself yields fewer rows).
offsetClause :: [Word64]
The offsetClause is combined with + to give an offset count if nonempty. The offset count says to skip that many rows before beginning to return rows. The rows are skipped before the limit count is applied.

Instances

OrderBy (TableExpression grp) grp Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods orderBy :: [SortExpression grp lat with db params from] -> TableExpression grp lat with db params from -> TableExpression grp lat with db params from Source #
Generic (TableExpression grp lat with db params from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Associated Types type Rep (TableExpression grp lat with db params from) :: Type -> Type # Methods from :: TableExpression grp lat with db params from -> Rep (TableExpression grp lat with db params from) x # to :: Rep (TableExpression grp lat with db params from) x -> TableExpression grp lat with db params from #
RenderSQL (TableExpression grp lat with db params from) Source #	Render a `TableExpression`
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods renderSQL :: TableExpression grp lat with db params from -> ByteString Source #
type Rep (TableExpression grp lat with db params from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table type Rep (TableExpression grp lat with db params from) = D1 (MetaData "TableExpression" "Squeal.PostgreSQL.Query.Table" "squeal-postgresql-0.6.0.1-2mcKKIXTe9UEFlpcl38Onr" False) (C1 (MetaCons "TableExpression" PrefixI True) ((S1 (MetaSel (Just "fromClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (FromClause lat with db params from)) :: (S1 (MetaSel (Just "whereClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [Condition Ungrouped lat with db params from]) :: S1 (MetaSel (Just "groupByClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (GroupByClause grp from)))) :: ((S1 (MetaSel (Just "havingClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (HavingClause grp lat with db params from)) :: S1 (MetaSel (Just "orderByClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [SortExpression grp lat with db params from])) :: (S1 (MetaSel (Just "limitClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [Word64]) :: S1 (MetaSel (Just "offsetClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [Word64])))))

from Source #

Arguments

:: FromClause lat with db params from	table reference
-> TableExpression Ungrouped lat with db params from

A from generates a TableExpression from a table reference that can be a table name, or a derived table such as a subquery, a JOIN construct, or complex combinations of these. A from may be transformed by where_, groupBy, having, orderBy, limit and offset, using the & operator to match the left-to-right sequencing of their placement in SQL.

where_ Source #

Arguments

:: Condition Ungrouped lat with db params from	filtering condition
-> TableExpression grp lat with db params from
-> TableExpression grp lat with db params from

A where_ is an endomorphism of TableExpressions which adds a search condition to the whereClause.

groupBy Source #

Arguments

:: SListI bys
=> NP (By from) bys	grouped columns
-> TableExpression Ungrouped lat with db params from
-> TableExpression (Grouped bys) lat with db params from

A groupBy is a transformation of TableExpressions which switches its Grouping from Ungrouped to Grouped. Use groupBy Nil to perform a "grand total" aggregation query.

having Source #

Arguments

:: Condition (Grouped bys) lat with db params from	having condition
-> TableExpression (Grouped bys) lat with db params from
-> TableExpression (Grouped bys) lat with db params from

A having is an endomorphism of TableExpressions which adds a search condition to the havingClause.

limit Source #

Arguments

:: Word64	limit parameter
-> TableExpression grp lat with db params from
-> TableExpression grp lat with db params from

A limit is an endomorphism of TableExpressions which adds to the limitClause.

offset Source #

Arguments

:: Word64	offset parameter
-> TableExpression grp lat with db params from
-> TableExpression grp lat with db params from

An offset is an endomorphism of TableExpressions which adds to the offsetClause.

Grouping

data By (from :: FromType) (by :: (Symbol, Symbol)) where Source #

Bys are used in groupBy to reference a list of columns which are then used to group together those rows in a table that have the same values in all the columns listed. By #col will reference an unambiguous column col; otherwise By2 (#tab ! #col) will reference a table qualified column tab.col.

Constructors

By1 :: (HasUnique table from columns, Has column columns ty) => Alias column -> By from '(table, column)
By2 :: (Has table from columns, Has column columns ty) => Alias table -> Alias column -> By from '(table, column)

Instances

(Has rel rels cols, Has col cols ty, by ~ (,) rel col) => IsQualified rel col (By rels by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods (!) :: Alias rel -> Alias col -> By rels by Source #
(Has rel rels cols, Has col cols ty, bys ~ ((,) rel col ': ([] :: [(Symbol, Symbol)]))) => IsQualified rel col (NP (By rels) bys) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods (!) :: Alias rel -> Alias col -> NP (By rels) bys Source #
(HasUnique rel rels cols, Has col cols ty, by ~ (,) rel col) => IsLabel col (By rels by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods fromLabel :: By rels by #
(HasUnique rel rels cols, Has col cols ty, bys ~ ((,) rel col ': ([] :: [(Symbol, Symbol)]))) => IsLabel col (NP (By rels) bys) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods fromLabel :: NP (By rels) bys #
Eq (By from by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods (==) :: By from by -> By from by -> Bool # (/=) :: By from by -> By from by -> Bool #
Ord (By from by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods compare :: By from by -> By from by -> Ordering # (<) :: By from by -> By from by -> Bool # (<=) :: By from by -> By from by -> Bool # (>) :: By from by -> By from by -> Bool # (>=) :: By from by -> By from by -> Bool # max :: By from by -> By from by -> By from by # min :: By from by -> By from by -> By from by #
Show (By from by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods showsPrec :: Int -> By from by -> ShowS # show :: By from by -> String # showList :: [By from by] -> ShowS #
RenderSQL (By from by) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods renderSQL :: By from by -> ByteString Source #

newtype GroupByClause grp from Source #

A GroupByClause indicates the Grouping of a TableExpression.

Constructors

UnsafeGroupByClause
Fields renderGroupByClause :: ByteString

Instances

Eq (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods (==) :: GroupByClause grp from -> GroupByClause grp from -> Bool # (/=) :: GroupByClause grp from -> GroupByClause grp from -> Bool #
Ord (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods compare :: GroupByClause grp from -> GroupByClause grp from -> Ordering # (<) :: GroupByClause grp from -> GroupByClause grp from -> Bool # (<=) :: GroupByClause grp from -> GroupByClause grp from -> Bool # (>) :: GroupByClause grp from -> GroupByClause grp from -> Bool # (>=) :: GroupByClause grp from -> GroupByClause grp from -> Bool # max :: GroupByClause grp from -> GroupByClause grp from -> GroupByClause grp from # min :: GroupByClause grp from -> GroupByClause grp from -> GroupByClause grp from #
Show (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods showsPrec :: Int -> GroupByClause grp from -> ShowS # show :: GroupByClause grp from -> String # showList :: [GroupByClause grp from] -> ShowS #
Generic (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Associated Types type Rep (GroupByClause grp from) :: Type -> Type # Methods from :: GroupByClause grp from -> Rep (GroupByClause grp from) x # to :: Rep (GroupByClause grp from) x -> GroupByClause grp from #
NFData (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods rnf :: GroupByClause grp from -> () #
RenderSQL (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods renderSQL :: GroupByClause grp from -> ByteString Source #
type Rep (GroupByClause grp from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table type Rep (GroupByClause grp from) = D1 (MetaData "GroupByClause" "Squeal.PostgreSQL.Query.Table" "squeal-postgresql-0.6.0.1-2mcKKIXTe9UEFlpcl38Onr" True) (C1 (MetaCons "UnsafeGroupByClause" PrefixI True) (S1 (MetaSel (Just "renderGroupByClause") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 ByteString)))

data HavingClause grp lat with db params from where Source #

A HavingClause is used to eliminate groups that are not of interest. An Ungrouped TableExpression may only use NoHaving while a Grouped TableExpression must use Having whose conditions are combined with .&&.

Constructors

NoHaving :: HavingClause Ungrouped lat with db params from
Having :: [Condition (Grouped bys) lat with db params from] -> HavingClause (Grouped bys) lat with db params from

Instances

Eq (HavingClause grp lat with db params from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods (==) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool # (/=) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool #
Ord (HavingClause grp lat with db params from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods compare :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Ordering # (<) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool # (<=) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool # (>) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool # (>=) :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> Bool # max :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> HavingClause grp lat with db params from # min :: HavingClause grp lat with db params from -> HavingClause grp lat with db params from -> HavingClause grp lat with db params from #
Show (HavingClause grp lat with db params from) Source #
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods showsPrec :: Int -> HavingClause grp lat with db params from -> ShowS # show :: HavingClause grp lat with db params from -> String # showList :: [HavingClause grp lat with db params from] -> ShowS #
RenderSQL (HavingClause grp lat with db params from) Source #	Render a `HavingClause`.
Instance details Defined in Squeal.PostgreSQL.Query.Table Methods renderSQL :: HavingClause grp lat with db params from -> ByteString Source #