Oracle 11g Release 2

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CREATE TABLE prefs (
  id   NUMBER(10,0) PRIMARY KEY,
  name VARCHAR2(50) NOT NULL UNIQUE,
  SchoolId NUMBER(10,0),
  UserId   NUMBER(10,0),
  YearID   NUMBER(4,0)
);
CREATE TABLE prefs_values (
  id NUMBER(10,0) REFERENCES prefs ( id ),
  value CHAR(1),
  PRIMARY KEY ( id, value )
)
INSERT INTO prefs ( id, name, schoolId, UserId, YearID )
VALUES ( 262806, 'AEADS|SAR|tdyCodes', 109, 0, 29 );
1 rows affected

INSERT INTO prefs_values( id, value )
SELECT 262806, 'T' FROM DUAL UNION ALL
SELECT 262806, 'L' FROM DUAL
2 rows affected

CREATE TABLE attendance_code ( id, att_code ) AS
SELECT 4903, 'L' FROM DUAL UNION ALL
SELECT 4902, 'X' FROM DUAL UNION ALL
SELECT 4901, 'T' FROM DUAL;
3 rows affected

SELECT id
FROM   attendance_code
WHERE  att_code IN (
  SELECT pv.value
  FROM   prefs_values pv
         INNER JOIN prefs p
         ON p.id = pv.id
  WHERE  p.name = 'AEADS|SAR|tdyCodes'
);


ID


4903

4901