SQL/MX 2.x Query Guide (H06.04+, J06.03+)

SQL/MX Operators
HP NonStop SQL/MX Query Guide—540437-005
7-4
Operators
Operators
BLOCKED_UNION Operator
The BLOCKED_UNION operator always executes the left child first and then the right
child. The execution of the right child is always blocked till the execution of the left child
completes. The description field for this operator contains:
The example of the BLOCKED_UNION operator is based on:
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
Rowset PACK
UNPACK
Sort SORT
Stored Function EXPLAIN
Tuple EXPR
TUPLELIST
VALUES
Token Followed by ... Data Type
fragment_id A sequential number assigned to the
fragment. 0 is always the master executor and
1 is reserved for the EXPLAIN plan. Numbers
2 to n will be ESP or DAM fragments.
integer
parent_frag The fragment_id for the parent fragment of the
current fragment. The value is (none) for the
master executor.
integer
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—if true, read from
left; if false, read from right.
expr(text)
union_type Merge, physical, or unspecified. text
condExpr Expression used for conditional union. Occurs
with the IF statement in compound
statements.
expr(text)
trigExceptExpr Expression used for trigger exceptions. expr(text)
Group Operator