pgsql: Improve error messages about misuse of SELECT INTO.

2021-08-21 Thread Tom Lane
Improve error messages about misuse of SELECT INTO. Improve two places in plpgsql, and one in spi.c, where an error message would confusingly tell you that you couldn't use a SELECT query, when what you had written *was* a SELECT query. The actual problem is that you can't use SELECT ... INTO in

pgsql: Improve error messages about misuse of SELECT INTO.

2021-08-21 Thread Tom Lane
Improve error messages about misuse of SELECT INTO. Improve two places in plpgsql, and one in spi.c, where an error message would confusingly tell you that you couldn't use a SELECT query, when what you had written *was* a SELECT query. The actual problem is that you can't use SELECT ... INTO in