Describe the bug

When unparsing a logical plan containing a LeftAnti Join or a LeftSemi Join operator with the unparser::dialect::PostgreSqlDialect, the resulting unparsed SQL contains LEFT ANTI JOIN or LEFT SEMI JOIN, respectively, which are not supported by Postgres. The same thing is true for other dialects such as unparser::dialect::MySqlDialect and unparser::dialect::SqliteDialect.

This causes issues when attempting to run federated queries in Datafusion over systems such as Postgres (namely, in the datafusion-table-providers repo).

I'm not sure if this is a bug or if the responsibility to generate valid SQL in a specific dialect should be delegated downstream. However, since there appears to be a previous PR with a similar issue (#10625), I leave this one here just in case.

To Reproduce

use datafusion::{
    error::Result,
    prelude::SessionContext,
    sql::unparser::{self, Unparser},
};

#[tokio::main]
async fn main() -> Result<()> {
    let ctx = SessionContext::new();
    ctx.sql("create table t1 (c int)").await?.collect().await?;
    ctx.sql("create table t2 (c int)").await?.collect().await?;

    let df = ctx
        .sql("select * from t1 where c not in (select c from t2)")
        .await?;

    let plan = df.into_optimized_plan()?; // optimizing the plan will introduce the LeftAnti Join
    println!("{}", plan);

    let sql = Unparser::new(&unparser::dialect::PostgreSqlDialect {}).plan_to_sql(&plan)?;
    println!("{}", sql);

    Ok(())
}

Which returns the (invalid in Postgres) query:

SELECT * FROM "t1" LEFT ANTI JOIN "t2" AS "__correlated_sq_1" ON "t1"."c" = "__correlated_sq_1"."c"

Expected behavior

Generate an equivalent valid query, such as:

SELECT * FROM t1 WHERE c NOT IN (SELECT c FROM t2)

Additional context

datafusion = "45.0.0"