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1. select :: forall a r (m :: Type -> Type) backend . (SqlSelect a r, MonadIO m, SqlBackendCanRead backend) => SqlQuery a -> ReaderT backend m [r]

   esqueleto	Database.Esqueleto

   Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return a list of rows. We've seen that from has some magic about which kinds of things you may bring into scope. This select function also has some magic for which kinds of things you may bring back to Haskell-land by using SqlQuery's return:

   • You may return a SqlExpr (Entity v) for an entity v (i.e., like the * in SQL), which is then returned to Haskell-land as just Entity v.
   • You may return a SqlExpr (Maybe (Entity v)) for an entity v that may be NULL, which is then returned to Haskell-land as Maybe (Entity v). Used for OUTER JOINs.
   • You may return a SqlExpr (Value t) for a value t (i.e., a single column), where t is any instance of PersistField, which is then returned to Haskell-land as Value t. You may use Value to return projections of an Entity (see (^.) and (?.)) or to return any other value calculated on the query (e.g., countRows or subSelect).
   The SqlSelect a r class has functional dependencies that allow type information to flow both from a to r and vice-versa. This means that you'll almost never have to give any type signatures for esqueleto queries. For example, the query select $ from $ \p -> return p alone is ambiguous, but in the context of

   do ps <- select $
   from $ \p ->
   return p
   liftIO $ mapM_ (putStrLn . personName . entityVal) ps
   

   we are able to infer from that single personName . entityVal function composition that the p inside the query is of type SqlExpr (Entity Person).

2. select :: forall a r (m :: Type -> Type) backend . (SqlSelect a r, MonadIO m, SqlBackendCanRead backend) => SqlQuery a -> ReaderT backend m [r]

   esqueleto	Database.Esqueleto.Experimental

   Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return a list of rows. We've seen that from has some magic about which kinds of things you may bring into scope. This select function also has some magic for which kinds of things you may bring back to Haskell-land by using SqlQuery's return:

   • You may return a SqlExpr (Entity v) for an entity v (i.e., like the * in SQL), which is then returned to Haskell-land as just Entity v.
   • You may return a SqlExpr (Maybe (Entity v)) for an entity v that may be NULL, which is then returned to Haskell-land as Maybe (Entity v). Used for OUTER JOINs.
   • You may return a SqlExpr (Value t) for a value t (i.e., a single column), where t is any instance of PersistField, which is then returned to Haskell-land as Value t. You may use Value to return projections of an Entity (see (^.) and (?.)) or to return any other value calculated on the query (e.g., countRows or subSelect).
   The SqlSelect a r class has functional dependencies that allow type information to flow both from a to r and vice-versa. This means that you'll almost never have to give any type signatures for esqueleto queries. For example, the query select $ from $ \p -> return p alone is ambiguous, but in the context of

   do ps <- select $
   from $ \p ->
   return p
   liftIO $ mapM_ (putStrLn . personName . entityVal) ps
   

   we are able to infer from that single personName . entityVal function composition that the p inside the query is of type SqlExpr (Entity Person).

3. select :: forall a r (m :: Type -> Type) backend . (SqlSelect a r, MonadIO m, SqlBackendCanRead backend) => SqlQuery a -> ReaderT backend m [r]

   esqueleto	Database.Esqueleto.Internal.Internal

   Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return a list of rows. We've seen that from has some magic about which kinds of things you may bring into scope. This select function also has some magic for which kinds of things you may bring back to Haskell-land by using SqlQuery's return:

   • You may return a SqlExpr (Entity v) for an entity v (i.e., like the * in SQL), which is then returned to Haskell-land as just Entity v.
   • You may return a SqlExpr (Maybe (Entity v)) for an entity v that may be NULL, which is then returned to Haskell-land as Maybe (Entity v). Used for OUTER JOINs.
   • You may return a SqlExpr (Value t) for a value t (i.e., a single column), where t is any instance of PersistField, which is then returned to Haskell-land as Value t. You may use Value to return projections of an Entity (see (^.) and (?.)) or to return any other value calculated on the query (e.g., countRows or subSelect).
   The SqlSelect a r class has functional dependencies that allow type information to flow both from a to r and vice-versa. This means that you'll almost never have to give any type signatures for esqueleto queries. For example, the query select $ from $ \p -> return p alone is ambiguous, but in the context of

   do ps <- select $
   from $ \p ->
   return p
   liftIO $ mapM_ (putStrLn . personName . entityVal) ps
   

   we are able to infer from that single personName . entityVal function composition that the p inside the query is of type SqlExpr (Entity Person).

4. select :: forall a r (m :: Type -> Type) backend . (SqlSelect a r, MonadIO m, SqlBackendCanRead backend) => SqlQuery a -> ReaderT backend m [r]

   esqueleto	Database.Esqueleto.Legacy

   Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return a list of rows. We've seen that from has some magic about which kinds of things you may bring into scope. This select function also has some magic for which kinds of things you may bring back to Haskell-land by using SqlQuery's return:

   • You may return a SqlExpr (Entity v) for an entity v (i.e., like the * in SQL), which is then returned to Haskell-land as just Entity v.
   • You may return a SqlExpr (Maybe (Entity v)) for an entity v that may be NULL, which is then returned to Haskell-land as Maybe (Entity v). Used for OUTER JOINs.
   • You may return a SqlExpr (Value t) for a value t (i.e., a single column), where t is any instance of PersistField, which is then returned to Haskell-land as Value t. You may use Value to return projections of an Entity (see (^.) and (?.)) or to return any other value calculated on the query (e.g., countRows or subSelect).
   The SqlSelect a r class has functional dependencies that allow type information to flow both from a to r and vice-versa. This means that you'll almost never have to give any type signatures for esqueleto queries. For example, the query select $ from $ \p -> return p alone is ambiguous, but in the context of

   do ps <- select $
   from $ \p ->
   return p
   liftIO $ mapM_ (putStrLn . personName . entityVal) ps
   

   we are able to infer from that single personName . entityVal function composition that the p inside the query is of type SqlExpr (Entity Person).

5. SELECT :: Mode

   esqueleto	Database.Esqueleto.Internal.Internal

   No documentation available.

6. selectFirst :: forall (m :: Type -> Type) record . (PersistQueryRead backend, MonadIO m, PersistRecordBackend record backend) => [Filter record] -> [SelectOpt record] -> ReaderT backend m (Maybe (Entity record))

   esqueleto	Database.Esqueleto

   Get just the first record for the criterion.

7. selectKeys :: forall record backend (m :: Type -> Type) . (PersistQueryRead backend, MonadResource m, PersistRecordBackend record backend, MonadReader backend m) => [Filter record] -> [SelectOpt record] -> ConduitM () (Key record) m ()

   esqueleto	Database.Esqueleto

   Get the Keys of all records matching the given criterion. For an example, see selectList.

8. selectKeysRes :: forall (m1 :: Type -> Type) (m2 :: Type -> Type) record . (PersistQueryRead backend, MonadIO m1, MonadIO m2, PersistRecordBackend record backend) => [Filter record] -> [SelectOpt record] -> ReaderT backend m1 (Acquire (ConduitM () (Key record) m2 ()))

   esqueleto	Database.Esqueleto

   Get the Keys of all records matching the given criterion.

9. selectOne :: forall a r (m :: Type -> Type) backend . (SqlSelect a r, MonadIO m, SqlBackendCanRead backend) => SqlQuery a -> ReaderT backend m (Maybe r)

   esqueleto	Database.Esqueleto

   Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return the first entry wrapped in a Maybe. @since 3.5.1.0

   Example usage

   firstPerson :: MonadIO m => SqlPersistT m (Maybe (Entity Person))
   firstPerson =
   selectOne $ do
   person <- from $ table @Person
   return person
   

   The above query is equivalent to a select combined with limit but you would still have to transform the results from a list:

   firstPerson :: MonadIO m => SqlPersistT m [Entity Person]
   firstPerson =
   select $ do
   person <- from $ table @Person
   limit 1
   return person
   

10. selectSource :: forall a r backend (m :: Type -> Type) . (SqlSelect a r, BackendCompatible SqlBackend backend, IsPersistBackend backend, PersistQueryRead backend, PersistStoreRead backend, PersistUniqueRead backend, MonadResource m) => SqlQuery a -> ConduitT () r (ReaderT backend m) ()

    esqueleto	Database.Esqueleto

    Execute an esqueleto SELECT query inside persistent's SqlPersistT monad and return a Source of rows.

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