Merry Christmas: draw a Christmas tree with GaussDB T and discuss the syntax compatibility of Gauss database

In the twinkling of an eye is the Christmas holiday, I wish you all a happy holiday. Draw a Christmas tree with GaussDB T (that is, GaussDB 100), pure domestic, more festive.

Without much to say, the picture above:

SQL is as follows:

SELECT

CASE WHEN ENMOTECH = 1 THEN lpad ('*'

GAO

'')

ELSE lpad (''

GAO + 1-ENMOTECH

'') | | rpad ('*'

Lag (ENMOTECH) OVER (PARTITION BY 1)

ORDER BY

ENMOTECH) + ENMOTECH-2

'*')

Merry Christmas, END.

FROM

(SELECT

LEVEL ENMOTECH

MAX (LEVEL) OVER (PARTITION BY 1) GAO

FROM dual

CONNECT BY LEVEL

< 19 ) UNION ALL SELECT lpad(lpad('*',3,'*'),19) FROM dual CONNECT BY LEVEL < 5; 主要，这段 SQL 代码，和 Oracle 完全兼容，在 Oracle 中执行效果如下：

To sum up, GaussDB works very happily after using a very special query syntax:

Case When

LAG analysis function

CONNECT by

Of course, Elder Yang said, my Christmas tree is not very good-looking. He drew a new one according to the company's congratulatory picture. Elder Yang said that the Christmas tree should be like this:

Let's take another picture:

The above code:

WITH leaf AS (

SELECT

Lpad (rpad ('*

(ROWNUM-1) * 2 + 1

'*')

ROWNUM + 20) leaf

ROWNUM

FROM

Dual

CONNECT BY

LEVEL