Setting custom variable

In MatrixOne, you can customize variables using the SET command and use them in SQL. The specific syntax is as follows:

  1. SET variable = expr, [variable = expr ..,]

Example

Now let’s define two variables, a and b:

  1. > SET  @a=2, @b=3;
  2. Query OK, 0 rows affected (0.00 sec)
  4. > select @a;
  5. +------+
  6. | @a   |
  7. +------+
  8. |    2 |
  9. +------+
  10. 1 row in set (0.00 sec)
  12. > select @b;
  13. +------+
  14. | @b   |
  15. +------+
  16. |    3 |
  17. +------+
  18. 1 row in set (0.00 sec)

Using custom variables in SQL:

  1. > create table t1(a int,b varchar(1));
  2. Query OK, 0 rows affected (0.02 sec)
  4. > insert into t1 values(@a,@b);
  5. Query OK, 1 row affected (0.02 sec)
  7. > select * from t1;
  8. +------+------+
  9. | a    | b    |
  10. +------+------+
  11. |    2 | 3    |
  12. +------+------+
  13. 1 row in set (0.01 sec)

Note

The variables a and b are both ints here. If you want a string of 2 or 3, it is recommended to use SET @a ='2', @b='3';.