SQL does allow/provide the following: SELECT l.id, cp.company_id, cp.part_id, coalesce(l.date_last_checked, cast(now() - INTERVAL '100 DAYS' as timestamp(0))) AS date_last_checked FROM last_checked l right join ( select c.id as company_id, p.id as part_id from Companies c cross join Parts p ) cp on l.company_id_fk = cp.company_id and l.part_id_fk = cp.part_id WHERE cp.company_id = 1 ; However, runtime might become a problem if Companies and Parts grow. At this time, you might want to switch to a UNION ALL of the two queries, which each provide part of the result, you need. See it in action: http://sqlfiddle.com/#!17/fcd97/1 Please comment, if and as this requires adjustment / further detail.

Simply: SELECT 'a' AS source, * FROM a UNION ALL -- NOT just UNION!! SELECT 'b' AS source, * FROM b -- matching row type! OFFSET :offset LIMIT :limit; The added source is optional. Unless using parentheses, LIMIT / OFFSET apply to the combined result set. While combined with UNION ALL, and no outer ORDER BY, you get rows from table a first, and rows from table b next. If you need a particular sort order, add ORDER BY per table with parentheses. Like: (SELECT * FROM a ORDER BY foo) UNION ALL (SELECT * FROM b ORDER BY bar) OFFSET :offset LIMIT :limit; Still no outer ORDER BY! However, LIMIT / OFFEST for pagination scales terribly for big tables. Consider instead: https://dba.stackexchange.com/questions/219782/efficient-pagination-for-big-tables/219810#219810 https://stackoverflow.com/a/34291099/939860

Locks are taken to preserve transaction isolation as described on the https://docs.microsoft.com/en-us/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-ver15#Basics doc. If the release of the lock doesn't hurt the ACID properties, there's no reason for SQL Server to keep a resource locked and, in fact, the sooner the lock is released the better for good performance. If you see the https://docs.microsoft.com/en-us/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-ver15#lock_modes , you'll find that the query from your question is most likely taking https://docs.microsoft.com/en-us/sql/relational-databases/sql-server-transaction-locking-and-row-versioning-guide?view=sql-server-ver15#shared : Shared (S) locks allow concurrent transactions to read (SELECT) a resource under pessimistic concurrency control. No other transactions can modify the data while shared (S) locks exist on the resource. Shared (S) locks on a resource are released as soon as the read operation completes, unless the transaction isolation level is set to repeatable read or higher, or a locking hint is used to retain the shared (S) locks for the duration of the transaction. [emphasis added] So no, the fact that your second query takes longer to run doesn't mean it causes the tables on the first one to be held util the end of the whole UNION. Microsoft has a doc on https://docs.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/bb677357(v=sql.105)?redirectedfrom=MSDN that uses Extended Events to exhibit the locks (acquired and released). I used the proposed session on a AdventureWorks2016 database to check the following query: SELECT ShoppingCartID, ModifiedDate FROM Sales.ShoppingCartItem UNION SELECT SalesOrderDetailID, ModifiedDate FROM Sales.SalesOrderDetail That query is similar to yours and you'll be able to see locks being acquired and released interchangeably, instead of only acquired at the beginning and released at the end.

Try this: SELECT DATE_FORMAT(`history_out`.date_mod, '%Y-%m-%d') AS "thedate", `history_out`.group, `history_out`.ticket AS "ticketOut", cast(NULL as unsigned int) AS "ticketIn", `history_out`.id FROM history `history_out` WHERE (`history_out`.prev_group IN (53042)) AND (`history_out`.date_mod >= @s) UNION ALL SELECT DATE_FORMAT(`history_in`.date_mod, '%Y-%m-%d') AS "thedate", `history_in`.group, NULL AS "ticketOut", `history_in`.ticket AS "ticketIn", `history_in`.id FROM history `history_in` WHERE (`history_in`.group IN (53042)) AND (`history_in`.date_mod >= @s); https://dbfiddle.uk/?rdbms=mysql_5.7&fiddle=3cb367f74ef955f0421d2db40fa1a5c3 PS. when I was working with RDBMS, the first select in a union decided the format of the columns. MySQL 5.7 may be as old.

You're missing a comma in the GROUP BY clause after the im.zona_sismica column. Your GROUP BY clause should be: GROUP BY Date_part('year', pr.data_chiusura), Date_part('month', pr.data_chiusura), regione.descrizione, provincia.descrizione, im.comune, im.zona_sismica, dati_ante.classe_rischio, dati_post.classe_rischio

Such issues have been considered for several years.References: https://github.com/dotnet/csharplang/blob/main/proposals/discriminated-unions.md ♪ https://github.com/dotnet/csharplang/issues/113 ♪ https://github.com/dotnet/csharplang/discussions/399 The quote from the last comment:" ..they will greatly facilitate the submission of data without excessive abuse of inheritance." (c)It was an over-inheritance, and I thought it was superfluous.Most interesting. https://github.com/mcintyre321/OneOf ♪In the example below, different types with no general interface are accepted by the method. OneOf He's returning common type.// Пихаем все в один НЕперегруженный метод, в точности как на TypeScript. PrintAsHex((50, 150, 250)); PrintAsHex(EnumColor.Red); PrintAsHex(new ClassColor()); // Без перегрузки выглядит намного лучше. void PrintAsHex(MultiTypeColor mtc) { // а здесь мы уже работаем с MultiTypeColor } Non-working snipe:using System; using System.Drawing; using OneOf; namespace DiscriminatedUnions { class Program { static void Main() { // Ну разве это не здорово Some.PrintAsHex((50, 150, 250)); Some.PrintAsHex(EnumColor.Red); Some.PrintAsHex(new ClassColor()); // Some.PrintAsRGB(new Some()); // А тут неизвестный тип => Error CS1503 } } class Some { // В теле метода имеем нужный нам тип public static void PrintAsHex(MultiTypeColor mtc) { Console.WriteLine(mtc.Hex); } } enum EnumColor { Red, Blue } class ClassColor { public byte R = 10; public byte G = 20; public byte B = 30; } // Если не обращать внимания на это безобразие, выше все выглядит достаточно прилично. class MultiTypeColor : OneOfBase<(byte, byte, byte), EnumColor, ClassColor> { Func<string, string> get = v => Enum.IsDefined(typeof(KnownColor), v) ? v : "White"; public Color Color { get; private set; } public string Hex { get => $"#{Color.R:X2}{Color.G:X2}{Color.B:X2}"; } MultiTypeColor(OneOf<(byte, byte, byte), EnumColor, ClassColor> ) : base() { Color = .Index switch { 0 => Color.FromArgb(.AsT0.Item1, .AsT0.Item2, .AsT0.Item3), 1 => Color.FromName(get(.AsT1.ToString())), 2 => Color.FromArgb(.AsT2.R, _.AsT2.G, _.AsT2.B), _ => Color.FromName("White") }; } public static implicit operator MultiTypeColor((byte, byte, byte) ) => new(); public static implicit operator MultiTypeColor(EnumColor ) => new(); public static implicit operator MultiTypeColor(ClassColor ) => new(); } }And there's a worker. https://dotnetfiddle.net/Ehc1Zk Typical, we don't break:Possible types are already known when the method is called.There's a parameter in the body. The lack of an implicit operator in Typescript♪I thought it was in the language, but it might have to wait a little.

In fact, the answer to the question is given in the text of a mistake - C does not make it possible to create an answer union No names, it's gnu expansion. Either turn on the expansion or make names.

Isn't it horizontal?SELECT Points AS val1, Goal1 & '/' & Shot1 AS val2, ... FROM Ext_GamePlayerStatsTVSport_temp temp, Players p, ( SELECT IIF(:TEAMID = TEAM,1,2) AS TEAMORDER FROM ( SELECT FIRSTTEAMID AS TEAM FROM Matches WHERE ID = :MATCHID ) ) WHERE :PLAYERID = p.ID AND temp.PlayerNumber = p.PlayerNumber AND temp.Teamorder=TEAMORDER If not, we'll have to do something likeSELECT CASE nums WHEN 1 THEN col1 WHEN 2 THEN col1 ... WHEN N THEN colN END AS value FROM (запрос выше) AS DATA, ( SELECT 1 AS num UNION SELECT 2 UNION ... SELECT N ) nums It's a syntaxy Axes.

Is that what you want?typedef union { float f; struct { unsigned short int lo, hi; }; } unionFloat; typedef struct { unionFloat data[32]; int size; } Mcalc;

Let's figure out what's real and what a union and enum are.enum is the listed type ( https://ravesli.com/urok-58-perechisleniya-tip-enum/ )e.g. type that can take 3 values - red, green and blueenum EColors { red, green, blue }; In your task, the only place to put this enum is the name of the destination, for example,enum EDestination { Moscow, Muhosranks, SaintPetersburg }; EDestination start = EDestination::Moscow; EDestination finish = EDestination::Muhosranks; union is a combination of several variables in one area of memory ( http://www.c-cpp.ru/books/obedineniya )e.g.union UNumbers { int num; char letter; } As a result, there will be two variables num (4 bath) and letter (1 Byte) in one variable in 4 Bayta.in modern programming, where resources are more scarce, union I'm sorry.What exactly do you want to unite into a union? Like the time of departure and the number of the train, provided we record the time of departure at 3 bayta, and the train number at 1 bay.union UTrainInfo { char departure[3]; int train_id; }; In this case, the number of trains will lie within the range of 0x01000 to 0xff00, and the time to record without minutes, for example, '115' will mean 11:50.P. S.It's much more convenient to use a simple structure with appropriate types.struct TrainData { std::string destination; // пункт назначения int id; // номер поезда int departure; // время отбытия };

https://docs.python.org/3/library/typing.html#typing.Union indicates that one of the types listed in square brackets may be relevant. For example Union[str, int] means that the type of line or number may be of value.Dict[Union[str, int], Union[str, Tuple[str, str]]] - a dictionary in which the keys are whole numbers or lines, and the values are rows or crusts of two strings.

#include <iostream> union Union { char a; int b; }; int main() { Union u{.b{42}}; std::cout << u.b << '\n'; } https://godbolt.org/z/q9zzeb

I'm suggesting that before the grouping, it'll be replaced in columns. pole_3 and pole_4 to the required. First, in grading table_number Group pole_1, pole2♪ And after that, we' be grouped into all fields to remove the duplicate lines. Replace the values with the end function https://docs.oracle.com/cd/B28359_01/server.111/b28286/functions059.htm#SQLRF00642 :select pole_1, pole_2, pole_3, pole_4 from (select pole_1, pole_2, first_value(pole_3) over(partition by pole_1, pole_2 order by table_number) pole_3, first_value(pole_3) over(partition by pole_1, pole_2 order by table_number) pole_4 from ( select t.*, 1 as table_number from table_1 t union all select t.*, 2 as table_number from table_2 t union all select t.*, 3 as table_number from table_3 t union all .... union all select t.*, 10 as table_number from table_10 t ) ) group by pole_1, pole_2, pole_3, pole_4 The second option is to renumber the lines within the future group and take the first:select pole_1, pole_2, pole_3, pole_4 from (select pole_1, pole_2, pole_3, pole_4 row_number() over(partition by pole_1, pole_2 order by table_number) RN from ( select t.*, 1 as table_number from table_1 t union all .... ) ) where RN=1

You can't do that. Do with+11 there's a clear restriction https://en.cppreference.com/w/cpp/language/union Unions cannot contain a non-static data member with a non-trivial special member function (copy constructor, copy-assignment operator, or destructor).I mean, int can, and string can't.After that, you can't do it in your syntaxis.In any case, this substance is a little strange and its use is very limited. For example, you can't pee in gold and read bronze.

Data myBite = {0}; myBite.c = 'k'; myBite.i <<= 8; myBite.c = 'A'; char* p = &d.c; cout << *p++ << *p; //вывод: AK The thing is, myBite.c at the same address as myBite.ithe symbol occupies 1 byte and the second (int) is 4 bytes. All we have to do is initiate these bikes right. We can achieve this by battering, and the address on the symbol will be the signer at the beginning of this "4th white area." Moreover, four symbols can be obtained:Data d = {0}; d.i = 'A'; d.i |= '.'<< 8; d.i |= 'K'<< 16; d.i |= '.' << 24; char* p = &d.c; for (int i = 0; i < 4; ++i) cout << *p++ ; //вывод: A.K.

Yes, language standard C (from C99)1(d) Allows one member unionand read:6.5.2.3 Structure and union members95) If the member used to read the contents of a union object is not the same as the member last used to store a value in the object, the appropriate part of the object representation of the value is reinterpreted as an object representation in the new type as described in 6.2.6 (a process sometimes called ‘type punning’. This might be a trap representation.However, it is clear from the quotation that this may result https://ru.stackoverflow.com/questions/838641 ♪ So the only safe option. calambour of typical (angl. type punning) by association - contact the member &apos; s value by type unsigned char or unsigned char []as this is the only type that is guaranteed not to contain trap representation:#include <stdio.h> #include <stdlib.h> int main(void) { union { int32_t i; unsigned char u[4]; } t; t.i = 13; for (size_t i = 0; i &lt; 4; ++i) printf("%02x", t.u[i]); } A special footnote was added toa C99. quote http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_257.htm : Finally, one of the changes from C90 to C99 was to remove any restriction on accessing one member of a union when the last store was to a different one. The rationale was that the behaviour would then depend on the representations of the values. Since this point is often misunderstood, it might well be worth making it clear in the Standard.

The first part made:SELECT TablePK.PositionPK, TableWT.PositionWT, TablePK.FirstName + ' ' + TablePK.LastName AS FullName, TablePK.StoreNumber, TablePK.StoreRegion, TablePK.Date, TablePK.PickRate, TableWT.WaitTime FROM (SELECT COUNT(*) AS PositionPK, NULL AS PositionWT, T1.UserID, T1.FirstName, T1.LastName, T1.StoreNumber, T1.StoreRegion, T1.Date, T1.PickRate, NULL AS WaitTime FROM Game.dbo.[user] T1, Game.dbo.[user] T2 WHERE T1.UserID = 'fd50lom' AND T2.PickRate >= T1.PickRate GROUP BY T1.UserID, T1.FirstName, T1.LastName, T1.StoreNumber, T1.StoreRegion, T1.Date, T1.PickRate) TablePK INNER JOIN (SELECT NULL AS PositionPK, COUNT(*) AS PositionWT, T1.UserID, T1.FirstName, T1.LastName, T1.StoreNumber, T1.StoreRegion, T1.Date, NULL AS PickRate, T1.WaitTime FROM Game.dbo.[user] T1, Game.dbo.[user] T2 WHERE T1.UserID = 'fd50lom' AND T2.WaitTime <= T1.WaitTime GROUP BY T1.UserID, T1.FirstName, T1.LastName, T1.StoreNumber, T1.StoreRegion, T1.Date, T1.WaitTime) TableWT ON TablePK.UserID = TableWT.UserID

I've decided. The fields of 1 byte are stored (This address and type, command and adata). They are accessed by the use of bat masks that are used in the relevant ghetters and grids. Thanks again, MSDN. 'Reinstate Monica' Knight for pushing in the right direction, and PashaPash for help in the process!Code C#: [StructLayout(LayoutKind.Explicit)] public struct PackageContainer { private const byte _pkg_type = 0xC0; private const byte _pkg_address = 0x3F; private const byte _pkg_cmd = 0xF0; private const byte _pkg_adata = 0x0F; [FieldOffset(0)] private byte pkg_type; [FieldOffset(0)] private byte pkg_address; [FieldOffset(1)] private byte pkg_cmd; [FieldOffset(1)] private byte pkg_adata; public byte Pkg_Type { // 2-битное значение get { return (byte)((pkg_type &amp; _pkg_type) &gt;&gt; 6); } set { pkg_type = (byte)((pkg_type &amp; ~_pkg_type) | (value &lt;&lt; 6) &amp; _pkg_type); } } public byte Pkg_Address { // 6-битное значение get { return (byte)(pkg_address &amp; _pkg_address); } set { pkg_address = (byte)((pkg_address &amp; ~_pkg_address) | (_pkg_address &amp; value)); } } } ♪ It's been good ♪ https://habr.com/ru/post/114953/ ♪

I can't use UNION because the Taliban have quite different formats.The non-stop fields are supplemented by literature (in this case NULL):SELECT NULL trainerID, NULL salary, data, abonementID, cost FROM payments UNION ALL SELECT trainerID, salary, data, NULL, NULL FROM payouts ORDER BY data

Not if I'm in union first fill the field u8Keyand then turn to the field u32Keythere's going to be an uncertain behavior. ♪ union At any time, no more than one field may be active and cannot be used to cast between these fields.