使用LPAD函數(shù)(MySQL、PostgreSQL、Oracle)可直接左補零，如LPAD(42, 5, '0')返回'00042';SQL Server可用RIGHT('00000' CAST(42 AS VARCHAR), 5) SQL Server 2012 ??(42, '00000')返回'00042';SQLite? printf('d', 42)? ?????.
SQL?? ?? 0? ?? ?? ??? ????? ?????? ???? ?? ??? ??? ??? ??? ? ????. ???? ????? ??? ???? ??? ?? ??? 0? ?? ??? ??? ???? ????.
LPAD ??(MySQL, PostgreSQL, Oracle)
??????? LPAD ? ???? ?? ??? ?? ??? ?????. ??? ??? ???? ???? ????. ???:
LPAD(??, ??_??, '0')
?:
LPAD ??(42, 5, '0'); -- '00042'? ?????.
LPAD ??(7, 4, '0'); -- '0007'? ?????.
RIGHT ? ??? ?? ??(SQL Server)
SQL Server?? LPAD? ??? RIGHT ? ??? ???? ?????? ? ????. ???:
RIGHT('00000' CAST(?? AS VARCHAR), total_length)
?:
SELECT RIGHT('00000' CAST(42 AS VARCHAR), 5); -- '00042'? ?????.
FORMAT ??(SQL Server 2012)
FORMAT ??? ???? ?? ???? ???? ?? ??? ??? ? ????. ???:
FORMAT(??, '00000')
?:
?? ??(42, '00000'); -- '00042'? ?????.
?? ??(123, '0000'); -- '0123'? ?????.
?????? ? ?
- ??? ?? ?? ??? ???? ?? ??????.
- ??? ?? ??? ?????(?: 4??, 6??).
- 0?? ??? ??? ???? ??? ?? ???? ??? ??????.
- SQLite??? ?? ??? ?? printf(' d', number)? ?????.
????? ?????? ???? ?? ??? ??????. LPAD? ??? ???? RIGHT CAST? SQL Server?? ????? FORMAT? ?? ??? ?? ? ?? ?? ??? ?????.
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