3.5. Returning Cursors PL/pgSQL functions can return cursors to the caller. This is useful to return multiple rows or columns, especially with very large result sets. To do this, the function opens the cursor and returns the cursor name to the caller (or simply opens the cursor using a p...
PostgreSQL proposes various built-in functions to deal with JSON data. TheJSON_AGG()is one such function that combines multiple values into a single JSON array. Using the JSON_AGG() function, a single column, multiple columns, or all columns of a table can be aggregated. The return type o...
zjh@postgres=#CREATEORREPLACEFUNCTIONpermutations2(aint, bint, cint)RETURNSSETOF abcAS$$BEGINRETURNNEXTa,b,c;END; $$ LANGUAGE plpgsql;CREATEFUNCTIONzjh@postgres=# zjh@postgres=# zjh@postgres=#select*frompermutations2(1,2,3); ERROR: query "SELECTa,b,c" returned3columns CONTEXT: PL/pgSQLfunc...
Using UNNEST() with Multiple Arrays You can unnest multiple arrays together using the UNNEST() function, ensuring that each array has the same length: code: -- Selecting all columnsSELECT*FROM-- Using the unnest() function to expand multiple arrays into individual rowsunnest(ARRAY[1,2,3],-...
pglogical.create_replication_set(set_name name, replicate_insert bool, replicate_update bool, replicate_delete bool, replicate_truncate bool) This function creates a new replication set. Parameters: set_name - name of the set, must be unique replicate_insert - specifies if INSERT is replicated, ...
Column 1 to Column N:This is the table’s column name. If we want to fetch data from a table using nullif function in PostgreSQL, we pass multiple columns simultaneously. Also, we have given the column name with the nullif function in PostgreSQL. ...
Group By –divide rows of a result set into groups and optionally apply an aggregate function to each group. Having –apply conditions to groups, which allow you to filter groups. Section 5. Set Operations Union –combine result sets of multiple queries into a single result set. Intersect –...
- Performed addition over the emp_salary and emp_bonus columns. - Utilized the COALESCE() function to deal with the NULL values. - In the COALESCE() function, we passed 0 as the second argument. - So, whenever a NULL value occurs in the emp_bonus column, the COALESCE() function will...
A First Function To write your first PL/pgSQL function, start with something simple: a function to return the Fibonacci number for a position in the Fibonacci sequence. I know, I know;everyoneuses a Fibonacci calculator to demonstrate code. Why can't I be original? Because ...
The above query will return the following result:The SELECT DISTINCT clause can be applied to multiple columns. In that case, the unique combination of all columns will be returned from the result set. Example: Get Distinct Values of Multiple Columns Copy SELECT DISTINCT city, weather FROM ...