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Add aggregate functions (#2925)

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The aggregate functions SUM(), MAX(), MIN(), AVG(), and COUNT() are now supported.
This commit is contained in:
Tim Abdulla
2023-11-23 14:03:03 -05:00
committed by GitHub
parent c3301a1653
commit 1c60b50e2e
29 changed files with 667 additions and 114 deletions
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src/PostgREST/ApiRequest/QueryParams.hs
+44 -23
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@@ -31,8 +31,8 @@ import Data.Tree (Tree (..))
import Text.Parsec.Error (errorMessages,
showErrorMessages)
import Text.ParserCombinators.Parsec (GenParser, ParseError, Parser,
anyChar, between, char, digit,
eof, errorPos, letter,
anyChar, between, char, choice,
digit, eof, errorPos, letter,
lookAhead, many1, noneOf,
notFollowedBy, oneOf,
optionMaybe, sepBy, sepBy1,
@@ -43,7 +43,8 @@ import PostgREST.RangeQuery (NonnegRange, allRange,
rangeOffset, restrictRange)
import PostgREST.SchemaCache.Identifiers (FieldName)
import PostgREST.ApiRequest.Types (EmbedParam (..), EmbedPath, Field,
import PostgREST.ApiRequest.Types (AggregateFunction (..),
EmbedParam (..), EmbedPath, Field,
Filter (..), FtsOperator (..),
Hint, JoinType (..),
JsonOperand (..),
@@ -58,7 +59,7 @@ import PostgREST.ApiRequest.Types (EmbedParam (..), EmbedPath, Field,
SimpleOperator (..), SingleVal,
TrileanVal (..))
import Protolude hiding (try)
import Protolude hiding (Sum, try)
data QueryParams =
QueryParams
@@ -99,7 +100,7 @@ data QueryParams =
-- 'select' is a reserved parameter that selects the fields to be returned:
--
-- >>> qsSelect <$> parse False "select=name,location"
-- Right [Node {rootLabel = SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectField {selField = ("location",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]
-- Right [Node {rootLabel = SelectField {selField = ("name",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectField {selField = ("location",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]
--
-- Filters are parameters whose value contains an operator, separated by a '.' from its value:
--
@@ -282,16 +283,16 @@ pTreePath = do
-- Parse select= into a Forest of SelectItems
--
-- >>> P.parse pFieldForest "" "id"
-- Right [Node {rootLabel = SelectField {selField = ("id",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]
-- Right [Node {rootLabel = SelectField {selField = ("id",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]
--
-- >>> P.parse pFieldForest "" "client(id)"
-- Right [Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("id",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]}]
-- Right [Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("id",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]}]
--
-- >>> P.parse pFieldForest "" "*,client(*,nested(*))"
-- Right [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "nested", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]}]}]
-- Right [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "client", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SelectRelation {selRelation = "nested", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]}]}]
--
-- >>> P.parse pFieldForest "" "*,...client(*),other(*)"
-- Right [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SpreadRelation {selRelation = "client", selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]},Node {rootLabel = SelectRelation {selRelation = "other", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing}, subForest = []}]}]
-- Right [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []},Node {rootLabel = SpreadRelation {selRelation = "client", selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]},Node {rootLabel = SelectRelation {selRelation = "other", selAlias = Nothing, selHint = Nothing, selJoinType = Nothing}, subForest = [Node {rootLabel = SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing}, subForest = []}]}]
--
-- >>> P.parse pFieldForest "" ""
-- Right []
@@ -299,7 +300,7 @@ pTreePath = do
-- >>> P.parse pFieldForest "" "id,clients(name[])"
-- Left (line 1, column 16):
-- unexpected '['
-- expecting letter, digit, "-", "->>", "->", "::", ")", "," or end of input
-- expecting letter, digit, "-", "->>", "->", "::", ".", ")", "," or end of input
--
-- >>> P.parse pFieldForest "" "data->>-78xy"
-- Left (line 1, column 11):
@@ -452,35 +453,37 @@ pRelationSelect :: Parser SelectItem
pRelationSelect = lexeme $ do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
name <- pFieldName
guard (name /= "count")
(hint, jType) <- pEmbedParams
try (void $ lookAhead (string "("))
return $ SelectRelation name alias hint jType
-- |
-- Parse regular fields in select
--
-- >>> P.parse pFieldSelect "" "name"
-- Right (SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Nothing})
-- Right (SelectField {selField = ("name",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name->jsonpath"
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selCast = Nothing, selAlias = Nothing})
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name::cast"
-- Right (SelectField {selField = ("name",[]), selCast = Just "cast", selAlias = Nothing})
-- Right (SelectField {selField = ("name",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Just "cast", selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "alias:name"
-- Right (SelectField {selField = ("name",[]), selCast = Nothing, selAlias = Just "alias"})
-- Right (SelectField {selField = ("name",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Just "alias"})
--
-- >>> P.parse pFieldSelect "" "alias:name->jsonpath::cast"
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selCast = Just "cast", selAlias = Just "alias"})
-- Right (SelectField {selField = ("name",[JArrow {jOp = JKey {jVal = "jsonpath"}}]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Just "cast", selAlias = Just "alias"})
--
-- >>> P.parse pFieldSelect "" "*"
-- Right (SelectField {selField = ("*",[]), selCast = Nothing, selAlias = Nothing})
-- Right (SelectField {selField = ("*",[]), selAggregateFunction = Nothing, selAggregateCast = Nothing, selCast = Nothing, selAlias = Nothing})
--
-- >>> P.parse pFieldSelect "" "name!hint"
-- Left (line 1, column 5):
-- unexpected '!'
-- expecting letter, digit, "-", "->>", "->", "::", ")", "," or end of input
-- expecting letter, digit, "-", "->>", "->", "::", ".", ")", "," or end of input
--
-- >>> P.parse pFieldSelect "" "*!hint"
-- Left (line 1, column 2):
@@ -495,18 +498,36 @@ pFieldSelect :: Parser SelectItem
pFieldSelect = lexeme $ try (do
s <- pStar
pEnd
return $ SelectField (s, []) Nothing Nothing)
<|> do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
fld <- pField
cast' <- optionMaybe (string "::" *> pIdentifier)
return $ SelectField (s, []) Nothing Nothing Nothing Nothing)
<|> try (do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
_ <- string "count()"
aggCast' <- optionMaybe (string "::" *> pIdentifier)
pEnd
return $ SelectField fld (toS <$> cast') alias
return $ SelectField ("*", []) (Just Count) (toS <$> aggCast') Nothing alias)
<|> do
alias <- optionMaybe ( try(pFieldName <* aliasSeparator) )
fld <- pField
cast' <- optionMaybe (string "::" *> pIdentifier)
agg <- optionMaybe (try (char '.' *> pAggregation <* string "()"))
aggCast' <- optionMaybe (string "::" *> pIdentifier)
pEnd
return $ SelectField fld agg (toS <$> aggCast') (toS <$> cast') alias
where
pEnd = try (void $ lookAhead (string ")")) <|>
try (void $ lookAhead (string ",")) <|>
try eof
pStar = string "*" $> "*"
pAggregation = choice
[ string "sum" $> Sum
, string "avg" $> Avg
, string "count" $> Count
-- Using 'try' for "min" and "max" to allow backtracking.
-- This is necessary because both start with the same character 'm',
-- and without 'try', a partial match on "max" would prevent "min" from being tried.
, try (string "max") $> Max
, try (string "min") $> Min
]
-- |