Postgres won't accept table alias before column name

问题

I'm using a framework (Jodd) which is adding the table alias to the column names in a SQL Select. It looks like well-formed SQL, but Postgres chokes on it.

update GREETING Greeting 
     set Greeting.ID=5, 
         Greeting.NAME='World', 
         Greeting.PHRASE='Hello World!'  
where (Greeting.ID=5)

gives an error:

Error: ERROR: column "greeting" of relation "greeting" does not exist
SQLState:  42703

Is there a way to get Postgres to accept that SQL? My other alternative is to hack the framework, which I don't want to do.

回答1:

The problem is that you include the table alias in SET clause, in the columns. See the documentation of UPDATE in Postgres docs:

column

The name of a column in table. The column name can be qualified with a subfield name or array subscript, if needed. Do not include the table's name in the specification of a target column — for example, UPDATE tab SET tab.col = 1 is invalid.

This is valid in Postgres:

update GREETING Greeting 
set 
    NAME='World', 
    PHRASE='Hello World!' 
where Greeting.ID=5 ;

回答2:

Check documentation on UPDATE statement, specifically for the column part: it is illegal to prefix columns with table alias in the SET clause.

UPDATE GREETING Greeting
   SET ID=5, NAME='World', PHRASE='Hello World!'
 WHERE (Greeting.ID=5);

回答3:

Try using the latest Jodd, v3.3.7. where this issue is fixed.

The problem was in the Jodd library: entity update methods were generating update statement with table aliases. The new version simply does not put table aliases; that works for Postgres and for other databases too.

来源：https://stackoverflow.com/questions/11369757/postgres-wont-accept-table-alias-before-column-name

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sql

postgresql

jodd