摘要:
In [21]: str1='' In [22]: for i in range(10): ...: str1=str1+str(i) ...: In [23]: str1 Out[23]: '0123456789' In [24]: str1[0:10] Out[24]: '0123456789' In [25]: str1[:10] Out[25]: '01... 阅读全文
摘要:
DECLARE NUM NUMBER; BEGIN SELECT COUNT(1) INTO NUM FROM ALL_TABLES WHERE TABLE_NAME = 'SIMPLE_CALC' ; IF NUM=1 THEN EXECUTE IMMEDIATE 'DROP TABLE simple_calc'; ... 阅读全文