#Sqlectron update commands update

The column name can be qualified with a subfield name or array subscript, if needed.

#Sqlectron update commands update

UPDATE statement must refer to this table as

When an alias is provided, it completely hides the actual name of the table. The name (optionally schema-qualified) of an existing table.Ī substitute name for the target table. When not specified, any tables inheriting from the named table are also processed. If specified, update rows from the named table only. See WITH Queries (Common Table Expressions) and SELECT for details. In such a case both sets of with_query can be referenced within the UPDATE query, but the second one takes precedence since it is more closely nested. It is possible for the query ( SELECT statement) to also contain a WITH clause. WITH clause allows you to specify one or more subqueries that can be referenced by name in theįor an UPDATE command that includes a WITH clause, the clause can only contain SELECT commands, the WITH clause cannot contain a data-modifying command ( INSERT, UPDATE, or DELETE). If count is 0, no rows matched the condition (this is not considered an error). Where count is the number of rows updated.

On successful completion, an UPDATE command returns a command tag of the form: UPDATE When the Global Deadlock Detector is enabled, the lock mode for UPDATE operations on heap tables is ROW EXCLUSIVE. NoteĪs the default, Greenplum Database acquires an EXCLUSIVE lock on tables for UPDATE operations on heap tables. You must also have the SELECT privilege on any column whose values are read in the expressions or condition. You must have the UPDATE privilege on the table, or at least on the column(s) that are listed to be updated. The WHERE CURRENT OF clause is not supported with replicated tables. If the WHERE CURRENT OF clause is specified, the row that is updated is the one most recently fetched from the specified cursor. Which technique is more appropriate depends on the specific circumstances. There are two ways to modify a table using information contained in other tables in the database: using sub-selects, or specifying additional tables in the FROM clause. If you wish to only update the specific table mentioned, you must use the ONLY clause. Only the columns to be modified need be mentioned in the SET clause columns not explicitly modified retain their previous values.īy default, UPDATE will update rows in the specified table and all its subtables.

UPDATE changes the values of the specified columns in all rows that satisfy the condition.