How to Update All Columns of a Record Without Having to List Every Column

How to UPDATE all columns of a record without having to list every column

It's not possible.

What you're trying to do is not part of SQL specification and is not supported by any database vendor. See the specifications of SQL UPDATE statements for MySQL, Postgresql, MSSQL, Oracle, Firebird, Teradata. Every one of those supports only below syntax:

UPDATE table_reference
   SET column1 = {expression} [, column2 = {expression}] ...
[WHERE ...]

How to update all columns with INSERT ... ON CONFLICT ...?

The UPDATE syntax requires to explicitly name target columns.
Possible reasons to avoid that:

• You have many columns and just want to shorten the syntax.
• You do not know column names except for the unique column(s).

"All columns" has to mean "all columns of the target table" (or at least "leading columns of the table") in matching order and matching data type. Else you'd have to provide a list of target column names anyway.

Test table:

CREATE TABLE tbl (
  id    int PRIMARY KEY
, text  text
, extra text
);

INSERT INTO tbl VALUES
  (1, 'foo')
, (2, 'bar')
;

1. DELETE & INSERT in single query instead

Without knowing any column names except id.

Only works for "all columns of the target table". While the syntax even works for a leading subset, excess columns in the target table would be reset to their respective column default (default NULL) with DELETE and INSERT.

UPSERT (INSERT ... ON CONFLICT ...) is needed to avoid concurrency / locking issues under concurrent write load, and only because there is no general way to lock not-yet-existing rows in Postgres (value locking).

Your special requirement only affects the UPDATE part. Possible complications do not apply where existing rows are affected. Those are locked properly. Simplifying some more, you can reduce your case to DELETE and INSERT:

WITH data(id) AS (              -- Only 1st column gets explicit name
   VALUES
      (1, 'foo_upd', 'a')       -- changed
    , (2, 'bar', 'b')           -- unchanged
    , (3, 'baz', 'c')           -- new
   )
, del AS (
   DELETE FROM tbl AS t
   USING  data d
   WHERE  t.id = d.id
   -- AND    t <> d              -- optional, to avoid empty updates
   )                             -- only works for complete rows
INSERT INTO tbl AS t
TABLE  data                      -- short for: SELECT * FROM data
ON     CONFLICT (id) DO NOTHING
RETURNING t.id;

In the Postgres MVCC model, an UPDATE is largely the same as DELETE and INSERT - except for some corner cases with concurrency, triggers, HOT updates, and big column values stored out of line, "TOASTed" values. Since you want to replace all rows anyway, just remove conflicting rows before the INSERT. Deleted rows remain locked until the transaction is committed. The INSERT might only find conflicting rows for previously non-existing key values if a concurrent transaction happens to insert them concurrently (after the DELETE, but before the INSERT).

You would lose additional column values for affected rows in this special case. No exception raised. But if competing queries have equal priority, that's hardly a problem: the other query won for some rows. Also, if the other query is a similar UPSERT, its alternative is to wait for this transaction to commit and then updates right away. "Winning" could be a Pyrrhic victory.

About "empty updates":

• How do I (or can I) SELECT DISTINCT on multiple columns?

No, my query must win!

OK, you asked for it:

WITH data(id) AS (                   -- Only 1st column gets explicit name
   VALUES                            -- rest gets default names "column2", etc.
     (1, 'foo_upd', NULL)            -- changed
   , (2, 'bar', NULL)                -- unchanged
   , (3, 'baz', NULL)                -- new
   , (4, 'baz', NULL)                -- new
   )
, ups AS (
   INSERT INTO tbl AS t
   TABLE  data                       -- short for: SELECT * FROM data
   ON     CONFLICT (id) DO UPDATE
   SET    id = t.id
   WHERE  false                      -- never executed, but locks the row!
   RETURNING t.id
   )
, del AS (
   DELETE FROM tbl AS t
   USING  data     d
   LEFT   JOIN ups u USING (id)
   WHERE  u.id IS NULL               -- not inserted!
   AND    t.id = d.id
   -- AND    t <> d                  -- avoid empty updates - only for full rows
   RETURNING t.id
   )
, ins AS (
   INSERT INTO tbl AS t
   SELECT *
   FROM   data
   JOIN   del USING (id)             -- conflict impossible!
   RETURNING id
   )
SELECT ARRAY(TABLE ups) AS inserted  -- with UPSERT
     , ARRAY(TABLE ins) AS updated;  -- with DELETE & INSERT

How?

• The 1st CTE data just provides data. Could be a table instead.
• The 2nd CTE ups: UPSERT. Rows with conflicting id are not changed, but also locked.
• The 3rd CTE del deletes conflicting rows. They remain locked.
• The 4th CTE ins inserts whole rows. Only allowed for the same transaction
• The final SELECT is optional, to show what happened.

To check for empty updates test (before and after) with:

SELECT ctid, * FROM tbl; -- did the ctid change?

The (commented out) check for any changes in the row AND t <> d works even with NULL values because we are comparing two typed row values according to the manual:

two NULL field values are considered equal, and a NULL is considered larger than a non-NULL

But all columns must support = / <> operators for the row comparison to work. See:

• How to query a json column for empty objects?

2. Dynamic SQL

This works for a subset of leading columns too, preserving existing values.

The trick is to let Postgres build the query string with column names from the system catalogs dynamically, and then execute it.

See related answers for code:

• Update multiple columns in a trigger function in plpgsql

• Bulk update of all columns

• SQL update fields of one table from fields of another one

Updating one column in all rows in a table

You're over-complicating the solution. In order to update every record, the approach you're trying to take is:

1. Select all records.
2. Get the ID for each record.
3. Loop through the IDs.
4. Update each record by that ID.

The UPDATE syntax has a much easier way to do this. You don't need to supply a WHERE clause to an UPDATE statement. Without that clause, it will by default update every record in the table:

UPDATE TableName SET `board`='value'

Also, please be aware that you have a SQL injection vulnerability in your code. By using
$_REQUEST['text'] directly in your SQL query, you allow any user to send SQL code to your query. Your code then executes whatever they send you. This could allow them to corrupt or delete your data, even gain administrative access to your server.

For starters, please stop using mysql_* functions. PHP has deprecated those and they should no longer be used. There is a mysqli_ replacement for them. In addition to that, use the mysqli_real_escape_string() function to sanitize your inputs before using them in a SQL query. And finally, use prepared statements instead of directly concatenating values into your SQL string.

can I update all the columns in one set

There is no SQL syntax to give you a quick and easy way of doing this that I know of.

One way you could do it is to write a PL/SQL block to select the column names of a given table from a system view e.g. user_tab_cols and write them to a variable to build up the SQL code to run dynamically. To be honest, unless you have a number of tables to do this on or loads of columns it would probably be easier to write the query manually.

EDIT - Here is the code incase you want it

declare
   v_table varchar2(50) := 'test_table';
   v_sql varchar2(2000) := null;

   cursor c_cols(p_table varchar2) is
      select c.column_name as col
        from user_tab_cols c
       where c.table_name = upper(p_table)
       order by c.column_id;

begin
   -- write first line of sql...
   v_sql := 'update ' || v_table || ' set' || chr(10);

   -- loop through col names to add each col into update statement...
   for l_c_cols in c_cols(v_table) loop
       v_sql := v_sql || l_c_cols.col || ' = trim(' || l_c_cols.col || '),' || chr(10);
   end loop;

   -- remove last comma...
   v_sql := substr(v_sql,1,length(v_sql)-2);

   -- run dynamic sql...
   dbms_output.put_line(v_sql);
   begin
      execute immediate v_sql;
      commit;
   end;

end;

Let me know if you have any questions on this.

How to select all the columns of a table except one column?

You can use this approach to get the data from all the columns except one:-

1. Insert all the data into a temporary table
2. Then drop the column which you dont want from the temporary table
3. Fetch the data from the temporary table(This will not contain the data of the removed column)
4. Drop the temporary table

Something like this:

SELECT * INTO #TemporaryTable FROM YourTableName

ALTER TABLE #TemporaryTable DROP COLUMN Columnwhichyouwanttoremove

SELECT * FROM #TemporaryTable 

DROP TABLE #TemporaryTable 

SQL - Update multiple records in one query

Try either multi-table update syntax

UPDATE config t1 JOIN config t2
    ON t1.config_name = 'name1' AND t2.config_name = 'name2'
   SET t1.config_value = 'value',
       t2.config_value = 'value2';

Here is a SQLFiddle demo

or conditional update

UPDATE config
   SET config_value = CASE config_name 
                      WHEN 'name1' THEN 'value' 
                      WHEN 'name2' THEN 'value2' 
                      ELSE config_value
                      END
 WHERE config_name IN('name1', 'name2');

Here is a SQLFiddle demo

How to update multiple columns having the same value or different values in SQL?

You can, by using a case expression, but whats the advantage?

update table_name set
  col1 = case when col1 = -99 then null /* or any new value for col1 */ else col1 end
  , col2 = case when col2 = -99 then null /* or any new value for col2 */ else col2 end
where col1 = -99 or col2 = -99;

Note, as pointed out by Larnu, when you are setting the column to null you can simplify the update to:

update table_name set
  col1 = nullif(col1,-99)
  , col2 = nullif(col2,-99)
where col1 = -99 or col2 = -99;

And you can change the values you are using (-99) on a per column basis to whatever you want e.g. col2 = 5

update table_name set
  col1 = nullif(col1,-99)
  , col2 = nullif(col2,5)
where col1 = -99 or col2 = 5;

Efficient way to update all rows in a table

The usual way is to use UPDATE:

UPDATE mytable
   SET new_column = <expr containing old_column>

You should be able to do this is a single transaction.

Postgres: Update all columns from another table

You could delete and re-insert, if the two tables have the same columns in the same order. Assuming that all records in tableB match tableA:

delete from tableA
    where id in (select id from tableB)

insert into tableA
    select *
    from tableB;

(If all records do not match, you could use a temporary table to keep the necessary ids.)

Generally, I oppose doing insert without a column list. In some cases, it is tolerable -- such as when tableB was created as a subset from tableB using *.

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