是否可以将所有数据从一个表复制到另一表以及一个额外的列? [英] Is it possible to copy all data from one table to another table, plus an extra column?

问题描述

我有两个稍微不同的表.表A有4列，而表B只有3列.我想将表B中的所有数据复制到表A中，但是我也想为每一行的每一列填充1值.

I have two tables that are very slightly different. Table A has 4 columns, and Table B has only 3. I want to copy all the data from Table B into Table A, but I also want to populate the extra column with the value 1 for every row.

如果不使用多余的列，这将起作用:

This would work if not for the extra column:

insert into TABLEA (COL1, COL2, COL3) select COL1, COL2, COL3 from TABLEB;

不幸的是，表A中的额外列不可为空，因此我不能再执行更新.

Unfortunately, the extra column in Table A is not nullable, so I can't just run an update afterwards.

感谢您的帮助！

推荐答案

指定列并使用常量作为值(请注意，您可以在select子句中混合使用常量和列引用).在这种情况下，我们指定每一行将为列COL4获得常数1.

Specify the column and use a constant for the value (note you can mix constants and column references in a select clause). In this case we're specifying every row will get the constant 1 for column COL4.

insert into TABLEA (COL1, COL2, COL3, COL4)
select COL1, COL2, COL3, 1
from TABLEB;

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