InterBase-SQL ,SELECT -Anweisung

[Robert_G]

@Leuselator
Man sollte für eine solche Einschränkungen neien StopKey verwenden (bei mir RowNum...)
Da bei deiner Variante ein zweiter kompletter Table access nötig war:

SQL-Code:

SELECT *
FROM   XXXXXXXXX.sent_queries t
WHERE  t.error_id >= 3000 And
       RowNum     =  1

Optimizer plan:

Delphi-Quellcode:

SELECT STATEMENT, GOAL = CHOOSE           CHOOSE                    SELECT STATEMENT
 COUNT STOPKEY                                             STOPKEY   COUNT
  TABLE ACCESS FULL    XXXXXXXXX   SENT_QUERIES           FULL      TABLE ACCESS

SQL-Code:

SELECT *
FROM   XXXXXXXXX.sent_queries t
WHERE  t.error_id = (SELECT Min(sq.error_id)
                     FROM   XXXXXXXXX.sent_queries sq
                     WHERE  sq.error_id  >= 3000)

Optimizer plan:

Delphi-Quellcode:

SELECT STATEMENT, GOAL = CHOOSE           CHOOSE                    SELECT STATEMENT
 FILTER                                                              FILTER
  TABLE ACCESS FULL    XXXXXXXXX   SENT_QUERIES           FULL      TABLE ACCESS
  SORT AGGREGATE                                          AGGREGATE SORT
   TABLE ACCESS FULL   XXXXXXXXX   SENT_QUERIES           FULL      TABLE ACCESS