mysql - selecting values from a table given column

2019-06-08 13:24发布

is it possible in mysql to select a value from a table by specifying the column number instead of the column name ?

3条回答
We Are One
2楼-- · 2019-06-08 14:12

I think for that you have to execute a single query using variables recursively. like using for loop to do that.

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▲ chillily
3楼-- · 2019-06-08 14:20

I don't think it is possible "directly" BUT with a query linked to the ORDINAL_POSITION field of the COLUMNS table from the information_schema should do the work!

Edit: COLUMNS table contains all the fields of all tables (and their positions)

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太酷不给撩
4楼-- · 2019-06-08 14:23

No, you can not use the ordinal value of a column in the SELECT clause.

Column order is irrelevant to a database; the ordinal value is based on the list of columns in the SELECT clause. The ordinal value is supported after the SELECT clause - IE: in the GROUP BY, and ORDER BY. That said, using ordinals is not a recommended approach because ordinals are brittle -- if someone changes the column order in the SELECT clause, the query can be negatively impacted.

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