What function do I need to get single quoted constants in the generated SQL? The code generator wraps the single-quoted output in double quotes

I wanted to create a view that sums a table common to a number of schemas, as expressed [here](https://dba.stackexchange.com/questions/333273/can-pl-pgsql-function-take-a-variable-number-of-parameters/333311#333311) , and includes the schema name or a derived expression as a column, so I created a view that includes the schema name as a constant value, by using the quote_literal to wrap the schema name in single quotes. The quote_literal may not be the right function here, but whatever I do gets wrapped in the double quotes. CREATE OR REPLACE FUNCTION create_summary_view_quoted( created_view text, common_view text, VARIADIC schemas text[] ) RETURNS text LANGUAGE sql AS $$SELECT format('CREATE VIEW %I AS ', created_view) || string_agg( format('SELECT %I as source_schema, * FROM %I.%I ', quote_literal(schemas[i]) , schemas[i], common_view), ' UNION ALL ' ) FROM generate_series(1, cardinality(schemas)) AS i$$; ") Applying it to the query SELECT create_summary_view_quoted('newv', 'oldv', 's1', 's2', 's3'); produces create view newv as select "'s1'" as source_schema, * from s1.oldv union all select "'s2'" as source_schema, * from s2.oldv union all select "'s3'" as source_schema, * from s3.oldv The problem is the double-quote around the single-quoted constant which causes Postgres to treat is as a column name and it barfs. I fixed the code generation issue by using double single quotes around the first placeholder and dropping the quote_literal function, i.e. replace format('SELECT %I as source_schema, * FROM %I.%I ', quote_literal(schemas[i]) , schemas[i], common_view), with format('SELECT ''%I'' as source_schema, * FROM %I.%I ', schemas[i] , schemas[i], common_view), My issue is not so much with quote_literal but how the function always wraps the output of any function which wraps a single-quoted string with double-quotes. Even when I used a function to strip off a leading suffix in the schema names because they are redundant the single quoted output gets wrapped in double quotes. eg quote_nullable(right(schemas[i],-10)) the resulting string gets double-quoted. I could apply the || operator somewhere there but I prefer a quoting function. Doesn't Postgres have a built-in single quoting function? Is there some required SQL syntax I'm missing? Is it a Postgres quirk?