View error in PostgreSQL

Question

I have a large query in a PostgreSQL database. The Query is something like this:

SELECT * FROM table1, table2, ... WHERE table1.id = table2.id...
         


        

Answer 1

No built-in way in the language to solve it (and frankly, * is a bad practice in general because it can cause latent defects to arise as the table schemas change - you can do table1.*, table2.acolumn, tabl2.bcolumn if you want all of one table and selectively from another), but if PostgreSQL supports INFORMATION_SCHEMA, you can do something like:

DECLARE @sql AS varchar

SELECT @sql = COALESCE(@sql + ', ', '') 
    + '[' + TABLE_NAME + '].[' + COLUMN_NAME + ']'
    + CHAR(13) + CHAR(10)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME IN ('table1', 'table2')
ORDER BY TABLE_NAME, ORDINAL_POSITION

PRINT @sql

And paste the results in to save a lot of typing. You will need to manually alias the columns which have the same name, of course. You can also code-gen unique names if you like (but I don't):

SELECT @sql = COALESCE(@sql + ', ', '') 
    + '[' + TABLE_NAME + '].[' + COLUMN_NAME + '] '
    + 'AS [' + TABLE_NAME + '_' + COLUMN_NAME + ']'
    + CHAR(13) + CHAR(10)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME IN ('table1', 'table2')
ORDER BY TABLE_NAME, ORDINAL_POSITION