插入内部十字架申请

Question

    SELECT DISTINCT CODE
    FROM   T1
    CROSS APPLY 
    (
        INSERT  INTO T4(TEXT1, TEXT2, TEXT3)
        SELECT  T2.TEXT1, T2.TEXT2, T3.TEXT3
        FROM    T2,
                T3
        WHERE   T2.ID = T3.ID
        AND     T2.CODE = T1.CODE
    ) AS T

When using executing this query I get this error:

A nested INSERT, UPDATE, DELETE, or MERGE statement must have an OUTPUT clause.

What am I doing wrong?

EDIT

What I was planning to achieve was simulate a WHILE..LOOP. Looping through all the CODEs in T1 and for each CODE get the TEXT fields from T2 and T3 (joining them with the ID) and insert them into table T4.

I am trying to separate the inserts by CODE because both tables have a large amount of data and I was trying to improve performance (maybe?!)

Answer 1

You can't do what you're attempting to do. The language will not allow you. To set the stage, I created the following 3 tables

SET NOCOUNT ON;
CREATE TABLE dbo.Final
(
    ID int IDENTITY(1,1) NOT NULL
,   text1 varchar(50) NOT NULL
,   text2 varchar(50) NOT NULL
,   text3 varchar(50) NOT NULL
);

CREATE TABLE dbo.Chain
(
    ID int NOT NULL
);

CREATE TABLE dbo.Chained
(
    ID int NOT NULL
,   Foo int NOT NULL
);

Just to demo where the OUTPUT clause goes, we will insert 4 rows and see the nice pretty INSERTED virtual table and the associated ID values.

-- Works
    INSERT INTO
        dbo.Final
    (
        text1
    ,   text2
    ,   text3
    )
    OUTPUT
        INSERTED.*
    SELECT
        D.t1
    ,   D.t2
    ,   D.t3    
    FROM
    (
        VALUES
            ('A', 'B', 'C')
        ,   ('D', 'B', 'C')
        ,   ('G', 'B', 'C')
        ,   ('J', 'B', 'C')
    ) D (t1,t2,t3);

Now, if I perform the following statement, it will work fine. However, if I neglect the INSERT just to visually inspect what I want to put into the table, SQL Server will raise the following error

A nested INSERT, UPDATE, DELETE, or MERGE statement is not allowed in a SELECT statement that is not the immediate source of rows for an INSERT statement.

-- Comment out the insert portion to generate
-- A nested INSERT, UPDATE, DELETE, or MERGE statement is not allowed in a SELECT statement that is not the immediate source of rows for an INSERT statement.
INSERT INTO
    dbo.Chain
(
    ID
)
SELECT
    X.ID
FROM
(
    INSERT INTO
        dbo.Final
    (
        text1
    ,   text2
    ,   text3
    )
    OUTPUT
        INSERTED.*
    SELECT
        D.t1
    ,   D.t2
    ,   D.t3    
    FROM
    (
        VALUES
            ('A', 'B', 'C')
        ,   ('D', 'B', 'C')
        ,   ('G', 'B', 'C')
        ,   ('J', 'B', 'C')
    ) D (t1,t2,t3)
) x

But, you want to go the extra mile and APPLY, or JOIN the results of that virtual table with something else and that's not going to fly.

A nested INSERT, UPDATE, DELETE, or MERGE statement is not allowed on either side of a JOIN or APPLY operator.

I suppose it's just one level of complexity too much.

-- Now, try the same bit except we use the derived table as a JOIN/APPLY
-- Can't fix what's not supported 
-- A nested INSERT, UPDATE, DELETE, or MERGE statement is not allowed on either side of a JOIN or APPLY operator.
INSERT INTO
    dbo.Chained
(
    ID
,   Foo
)
SELECT
    X.ID
,   D.foo
FROM
(
    VALUES
    (1)
) D(Foo)
CROSS APPLY
(
    INSERT INTO
        dbo.Final
    (
        text1
    ,   text2
    ,   text3
    )
    OUTPUT
        INSERTED.*
    SELECT
        D.t1
    ,   D.t2
    ,   D.t3    
    FROM
    (
        VALUES
            ('A', 'B', 'C')
        ,   ('D', 'B', 'C')
        ,   ('G', 'B', 'C')
        ,   ('J', 'B', 'C')
    ) D (t1,t2,t3)
) x;

If you really need something like that, then you'll have to break it out into separate statements.

Answer 2

Kind of a guess

INSERT  INTO FINAL (TEXT1   , TEXT2   , TEXT3)
SELECT  DISTINCT    T2.TEXT1, T2.TEXT2, T3.TEXT3
  FROM  T1
  JOIN  T2
   on   T2.ID = T1.ID
  JOIN  T3
    on  T3.VALUE = T2.VALUE