SQL/MX 3.1 Query Guide (H06.23+, J06.12+)

SQL/MX Operators
HP NonStop SQL/MX Release 3.1 Query Guide—663851-001
7-55
ORDERED_UNION Operator
The following is an example of the ORDERED_UNION operator:
create table table_a
(col1 char(5) NOT NULL NOT DROPPABLE
, col2 int NOT NULL NOT DROPPABLE
, col3 smallint
, CONSTRAINT table_a_PRIMARY_KEY PRIMARY KEY (col1 ASC, col2
ASC) NOT DROPPABLE
);
create table table_b
(col1 char(5) NOT NULL NOT DROPPABLE
, col2 int NOT NULL NOT DROPPABLE
, col3 smallint
, owner_count int
, CONSTRAINT table_b_PRIMARY_KEY PRIMARY KEY (col1 ASC, col2
ASC) NOT DROPPABLE
);
ALTER TABLE table_a
ADD CONSTRAINT table_a_KEY FOREIGN KEY
(col1, col2) REFERENCES
table_b(col1, col2) on update restrict on delete restrict
DROPPABLE ;
CREATE TRIGGER table_a_Owner_Count
AFTER INSERT ON table_a
REFERENCING NEW AS newrow
FOR EACH ROW
UPDATE table_b SET owner_count = (
SELECT count(*) FROM table_a
WHERE (table_b.col1,table_b.col2)=
(table_a.col1,table_a.col2)
AND table_a.col3 = 1
)
WHERE (table_b.col1,table_b.col2)=
(newrow.col1,newrow.col2);
insert into table_b values('A', 1, 1, 0);
fragment_type Master, ESP, or DP2. text
sort_order Sort order of the result of the union. text
merge_expression Expression used to determine which child
operator to read from next—read from left if true
and read from right if false.
expr(text)
union_type Merge, physical or unspecified. text
condExpr Expression used for conditional union. Occurs
with IF statement in compound statements.
expr(text)
trigExceptExpr Expression used for trigger exceptions. expr(text)
TP663851.fm Page 55 Monday, October 17, 2011 11:48 AM