17.10 - 例: RESPECT NULLSを使用するLAG - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL関数、式、および述部

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
2021年7月
Content Type
プログラミング リファレンス
Publication ID
B035-1145-171K-JPN
Language
日本語 (日本)

ANSIスタイルの構文:

SELECT empno, empname, job, sal,
       LAG(sal, 1, 0) RESPECT NULLS
       OVER (PARTITION BY job ORDER BY empno) AS sal_prev
FROM   emp
ORDER BY job, empno;

 EMPNO      EMPNAME     JOB        SAL      SAL_PREV
---------- ---------- --------- ---------- ----------
   12        PAUL       ANALYST    ?          0
   13        GRACE      ANALYST    3000       ?
   1         JOHN       CLERK      800        0
   2         ERIC       CLERK      950        800
   3         KURT       CLERK      ?          950
   6         JULIE      CLERK      1300       ?
   9         NICHOLAS   MANAGER    2450       0
   10        NOVAK      MANAGER    ?          2450
   11        ROGER      MANAGER    2850       ?
   14        RICH       PRESIDENT  5000       0
   4         KENT       SALESMAN   1250       0
   5         LYNN       SALESMAN   ?          1250
   7         TERESA     SALESMAN   1500       ?
   8         MATTHEW    SALESMAN   1600       1500

Teradataスタイルの構文:

SELECT empno, empname, job, sal,
       LAG(sal RESPECT NULLS, 1, 0) 
       OVER (PARTITION BY job ORDER BY empno) AS sal_prev
FROM   emp
ORDER BY job, empno;

 EMPNO      EMPNAME     JOB        SAL      SAL_PREV
---------- ---------- --------- ---------- ----------
   12        PAUL       ANALYST    ?          0
   13        GRACE      ANALYST    3000       ?
   1         JOHN       CLERK      800        0
   2         ERIC       CLERK      950        800
   3         KURT       CLERK      ?          950
   6         JULIE      CLERK      1300       ?
   9         NICHOLAS   MANAGER    2450       0
   10        NOVAK      MANAGER    ?          2450
   11        ROGER      MANAGER    2850       ?
   14        RICH       PRESIDENT  5000       0
   4         KENT       SALESMAN   1250       0
   5         LYNN       SALESMAN   ?          1250
   7         TERESA     SALESMAN   1500       ?
   8         MATTHEW    SALESMAN   1600       1500