How to build an INSERT query in PLPGSQL in a LOOP that will execute only once

In PL/pgSQL, the procedural language for PostgreSQL, you can use a LOOP statement to execute a block of code multiple times. This is often useful when you need to insert multiple rows into a database table. To construct an INSERT query inside a PL/pgSQL LOOP, you can use the CONCAT function and a string variable.

First, declare a variable to hold the INSERT query as a string. For example, you can use the following code:

DECLARE
query TEXT;
BEGIN
-- Other code here
query := 'INSERT INTO table_name (column1, column2) VALUES ';
-- Construct the rest of the query here
END;

Next, use a LOOP statement to iterate through the data and construct the INSERT query. For example, you can use a SELECT statement to retrieve the data and store it in a record variable, then use a FOR loop to iterate through the records:

FOR record_variable IN SELECT * FROM source_table LOOP
query := CONCAT(query, '(''', record_variable.column1, ''', ''', record_variable.column2, '''), ');
END LOOP;

Inside the loop, the CONCAT function is used to append each set of values to the query string. The values are enclosed in single quotes and separated by commas. Note that the last value in the query should not have a trailing comma, so you may need to remove it after the loop.

Finally, after the loop, you can execute the constructed INSERT query using the EXECUTE statement:

EXECUTE query;

This will execute the INSERT statement once with all the constructed values. You can then use the COMMIT statement to commit the changes to the database.

By following these steps, you can construct an INSERT query in PL/pgSQL in a LOOP to execute it once and insert multiple rows into a database table.

Constructing an INSERT query in PL/pgSQL within a LOOP

When working with PL/pgSQL, it is often necessary to construct INSERT queries in a loop to insert multiple rows into a table. This can be achieved by dynamically building the INSERT query and executing it within the loop.

Here is an example of how to construct an INSERT query in PL/pgSQL within a LOOP:

  1. First, declare variables that will hold the values for each row you want to insert.
  2. Create a LOOP to iterate over the data you want to insert.
  3. Inside the loop, assign the values for each row to the variables.
  4. Use the CONCAT function to dynamically build the INSERT query using the variables.
  5. Execute the INSERT query using the EXECUTE statement.

Below is the code example:

DECLARE
row_value1 INTEGER;
row_value2 VARCHAR(255);
BEGIN
FOR i IN 1..5 LOOP
row_value1 := i;
row_value2 := 'Value '

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