postgresql的substr()函數

原創 付月半子 2020-04-29 00:53

select substr('1234',0,3) as re

 

如果是pg：得到的結果是12

如果是oracle：得到的結果是123

如果是mysql：得到的結果是空

因爲pg和mysql的substr()函數的第一個位置都是爲1的，pg爲0的時候返回數據是有值的，但mysql爲0時候返回數據爲空了

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