I'm trying to do an INSERT INTO a table whose name is in the variable myTable.

In MySQL, I'd do it like this:

SET @SQL = CONCAT('INSERT INTO ',myschema'.'mytable,' SELECT action_name, user, ...');

I checked into postgreSQL documentation for prepared statements, and I couldn't find any similar examples.

I can assemble query into a string:

sql_query := 'INSERT INTO ' || mySchema || '.' || myTable || ' SELECT action_name, user, ';

But how do I execute it?


To write procedural code and use variables with PostgreSQL, the most common way is to use the plpgsql language, in a function or in a DO block. Executing Dynamic Commands in the documentation has all the details you need.

Note that a dynamic SQL statement does not require a PREPARE like in your MySQL example. It's possible to EXECUTE a dynamic string directly containing the SQL query, and in most cases that's how it's done.

What might be confusing to a beginner in Postgres is that it has two distinct forms of EXECUTE:

  • EXECUTE command-string [ INTO [STRICT] target ] [ USING expression [, ... ] in a plpgsql code block is a plpgsql instruction.

  • EXECUTE name [ ( parameter [, ...] ) ] is an SQL query, where name is the name of prepared statement previously declared with PREPARE.

| improve this answer | |
  • I'm still getting error: ERROR: missing FROM-clause entry for table "new" LINE 1: INSERT INTO public.dev_hist SELECT $1, user, NEW.* – Granny Aching Mar 8 '19 at 16:50
  • @GrannyAching ...USING NEW is accepted in plpgsql. You probably want to use that. – Daniel Vérité Mar 8 '19 at 18:52

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