Question

我知道在SQL Server中，可以使用没有FROM子句的SELECT子句，并创建一个包含一行和一列的表

SELECT 1 AS n;

但我只是想知道，是否可以使用没有FROM子句的SELECT子句来创建

包含一列多行的表
包含多列和一行的表
包含多列和多行的表

我尝试了许多组合，例如

SELECT VALUES(1, 2) AS tableName(n, m);

没有成功。

Answer 1

您可以使用CTE并使用union（如果您想要显示重复项，请使用union all）

Rextester Sample for all 3 scenarios

一列多行

with tbl1(id) as
(select 1 union all
 select 2)
select * from tbl1;

一行多列

with tbl2(id,name) as
(select 1,'A')
select * from tbl2;

多列和多行

with tbl3(id,name) as
(select 1,'A' union all
select 2,'B')
select * from tbl3;

Answer 2

-- One column, multiple rows.
select 1 as ColumnName union all select 2; -- Without FROM;
select * from ( values ( 1 ), ( 2 ) ) as Placeholder( ColumnName ); -- With FROM.

-- Multiple columns, one row.
select 1 as TheQuestion, 42 as TheAnswer; -- Without FROM.
select * from ( values ( 1, 42 ) ) as Placeholder( TheQuestion, TheAnswer ); -- With FROM.

-- Multiple columns and multiple rows.
select 1 as TheQuestion, 42 as TheAnswer union all select 1492, 12; -- Without FROM.
select * from ( values ( 1, 2 ), ( 2, 4 ) ) as Placeholder( Column1, Column2 ); -- With FROM.

Answer 3

您可以使用UNION关键字

完成所有操作

create table tablename as select 1 as n,3 as m union select 2 as n,3 as m

在Oracle中它将是双重的：

create table tablename as select 1 as n,3 as m from dual union select 2 as n,3 as m from dual

Answer 4

您可以使用UNION运算符：

CREATE TABLE AS SELECT column_name(s) FROM table1
UNION
SELECT column_name(s) FROM table2;

UNION运算符默认情况下仅选择不同的值。要允许重复值，您可以使用UNION ALL 结果集中的列名通常等于UNION中第一个SELECT语句中的列名。

Answer 5

试试这个：

--1) a table with one column and multiple rows
select * into tmptable0 from(
select 'row1col1' as v1
union all
select 'row2col1' as v1
) tmp

--2) a table with multiple columns and one row
select  'row1col1' as v1, 'row1col2' as v2 into tmptable1

--3) a table with multiple columns and multiple rows
select * into tmptable2 from(
select 'row1col1'  as v1, 'row1col2' as v2 
union all
select 'row2col1' as v2, 'row2col2' as v2 
) tmp

Answer 6

一个人可以创建一个视图，然后在需要时可以查询它

-- 一列多行表格

create view vw1 as
(
 select 'anyvalue' as col1
 union all
 select 'anyvalue' as col1
)

select * from vw1

-- 多列多行表格

create view vw2 as
(
 select 'anyvalue1' as col1, 'anyvalue1' as col2
 union all 
 select 'anyvalue2' as col1, 'anyvalue2' as col2
)

select * from vw2

如何仅使用SELECT子句创建具有多个行和列的表（即使用SELECT without FROM子句）

6 个答案: