Learning PostgreSQL 11 - Third Edition

The FOR loop statement

PL/pgSQL provides two forms of the FOR statement, and they are used to execute the following:

• Iterate through the rows returned by an SQL query
• Iterate through a range of integer values

The syntax of the FOR loop statement is as follows:

[ <<label>> ]FOR name IN [ REVERSE ] expression1 .. expression2 [ BY expression ] LOOP    statementsEND LOOP [ label ];

The name parameter is the name of a local variable of the integer type. This local variable scope is the FOR loop. Statements inside of the loop can read this variable but cannot change its value. Finally, you can change this behavior by defining the variable in the declaration section of the outer block. expression1 and expression2 must be evaluated to integer values; ...