Hur uppdaterar man alla rader utom en rad av många som uppfyller det givna villkoret?

Eftersom du inte bryr dig om ordningen på rader när du uppdaterar tabellen kan du helt enkelt använda MIN och GRUPPER EFTER .

Uppdatera Du måste gruppera efter colA och colC .

Till exempel,

Inställningar

SQL> CREATE TABLE t
  2    (
  3      COlA VARCHAR2(12),
  4      COLB VARCHAR2(9),
  5      COLC VARCHAR2(5),
  6      COLD VARCHAR2(5),
  7      COLE VARCHAR2(1)
  8    );

Table created.

SQL> INSERT ALL
  2      INTO t (COlA, COLB, COLC, COLD, COLE)
  3           VALUES ('Equipment SI', 'ADD INFO', 'MERGE', 'Notes', 'Y')
  4      INTO t (COlA, COLB, COLC, COLD, COLE)
  5           VALUES ('Equipment SI', 'Active', 'MERGE', 'Notes', 'Y')
  6      INTO t (COlA, COLB, COLC, COLD, COLE)
  7           VALUES ('Equipment SI', 'ORIGINAL', 'MERGE', 'Notes', 'Y')
  8      INTO t (COlA, COLB, COLC, COLD, COLE)
  9           VALUES ('Fastening', 'ADD INFO', 'MERGE', 'Notes', 'Y')
 10      INTO t (COlA, COLB, COLC, COLD, COLE)
 11           VALUES ('Fastening', 'Active', 'MERGE', 'Notes', 'Y')
 12      INTO t (COlA, COLB, COLC, COLD, COLE)
 13           VALUES ('Electonics', 'ADD INFO', 'MERGE', 'Notes', 'Y')
 14      INTO t (COlA, COLB, COLC, COLD, COLE)
 15           VALUES ('Electonics', 'Active O', 'MERGE', 'Notes', 'Y')
 16      INTO t (COlA, COLB, COLC, COLD, COLE)
 17           VALUES ('Electonics', 'ORIGINAL', 'MERGE', 'Notes', 'Y')
 18      INTO t (COlA, COLB, COLC, COLD, COLE)
 19           VALUES ('Electonics', 'Nominated', 'MERGE', 'Notes', 'Y')
 20      INTO t (COlA, COLB, COLC, COLD, COLE)
 21           VALUES ('Fiber', 'ADD INFO', 'MULTI', 'Notes', 'Y')
 22      INTO t (COlA, COLB, COLC, COLD, COLE)
 23           VALUES ('Fiber', 'ADD INFO', 'KILO', 'Notes', 'Y')
 24  SELECT * FROM dual;

11 rows created.

SQL> COMMIT;

Commit complete.

Tabelldata

SQL> SELECT * FROM t;

COLA         COLB      COLC  COLD  C
------------ --------- ----- ----- -
Equipment SI ADD INFO  MERGE Notes Y
Equipment SI Active    MERGE Notes Y
Equipment SI ORIGINAL  MERGE Notes Y
Fastening    ADD INFO  MERGE Notes Y
Fastening    Active    MERGE Notes Y
Electonics   ADD INFO  MERGE Notes Y
Electonics   Active O  MERGE Notes Y
Electonics   ORIGINAL  MERGE Notes Y
Electonics   Nominated MERGE Notes Y
Fiber        ADD INFO  MULTI Notes Y
Fiber        ADD INFO  KILO  Notes Y

11 rows selected.

Uppdatera uttalande

SQL> UPDATE t
  2  SET colE         = 'N'
  3  WHERE ROWID NOT IN
  4    ( SELECT MIN(rowid) FROM t GROUP BY colA, colC
  5    );

6 rows updated.

Låt oss kolla

SQL> SELECT * FROM t;

COLA         COLB      COLC  COLD  C
------------ --------- ----- ----- -
Equipment SI ADD INFO  MERGE Notes Y
Equipment SI Active    MERGE Notes N
Equipment SI ORIGINAL  MERGE Notes N
Fastening    ADD INFO  MERGE Notes Y
Fastening    Active    MERGE Notes N
Electonics   ADD INFO  MERGE Notes Y
Electonics   Active O  MERGE Notes N
Electonics   ORIGINAL  MERGE Notes N
Electonics   Nominated MERGE Notes N
Fiber        ADD INFO  MULTI Notes Y
Fiber        ADD INFO  KILO  Notes Y

11 rows selected.

SQL>