Difference between Insert and Insert all

Question

Hi,
I tried to understand what INSERT ALL syntax is doing, but I cannot find any difference between INSERT and INSERT ALL.
I replicated the test scenario using the data from the below mentioned URL:
http://psoug.org/reference/insert.html
I also did a google on finding up the difference between them, but could not find any...
Please advice if both are same as I have planned to use INSERT statement with a WHEN clause if INSERT ALL is same as INSERT.
Thanks!

Answer 1

Hello
The key difference is that INSERT ALL will allow you to insert into multiple different tables in a single statement whereas INSERT will only insert into 1 table. Each of the WHEN clauses allows a different table to be specified.
SQL> create table t1
  2  (   id  number
  3  )
  4  /
Table created.
Elapsed: 00:00:00.01
SQL> create table t2
  2  (   id  number
  3  )
  4  /
Table created.
Elapsed: 00:00:00.00
SQL> create table t3
  2  (   id  number
  3  )
  4  /
Table created.
SQL> INSERT
  2  ALL
  3      WHEN id < 10 THEN
  4          INTO t1 VALUES(id)
  5      WHEN MOD(id,2) = 0 THEN
  6          INTO t2 VALUES(id)
  7      WHEN MOD(id,2) != 0 THEN
  8          INTO t3 VALUES(id)
  9  SELECT
10      rownum id
11  FROM
12      dual
13  CONNECT BY
14      LEVEL <=20
15  /
29 rows created.
Elapsed: 00:00:00.01
SQL> select * from t1;
        ID
         1
         2
         3
         4
         5
         6
         7
         8
         9
9 rows selected.
Elapsed: 00:00:00.01
SQL> select * from t2;
        ID
         2
         4
         6
         8
        10
        12
        14
        16
        18
        20
10 rows selected.
Elapsed: 00:00:00.00
SQL> select * from t3
  2  /
        ID
         1
         3
         5
         7
         9
        11
        13
        15
        17
        19
10 rows selected.
Elapsed: 00:00:00.01So you can see that in a single statement, I've inserted all rows with an ID <10 into t1, all even numbered rows into t2 and all odd numbered rows into t3. This was also done with a single pass of the source table - in this case dual.
David