fix bugs explain with non-correlated query #395

Job	Run time
Check cargo fmt	40s
cargo test (macos)	5m 4s
build with wasm-pack	2m 35s
cargo check	7m 12s
cargo test (macos-aarch64)	9m 6s
Verify MSRV (Min Supported Rust Version)	8m 10s
Verify Vendored Code	48s
cargo test (win64)	12m 1s
cargo test datafusion-cli (amd64)	3m 55s
cargo test (amd64)	6h 0m 2s
cargo doc	4m 9s
cargo test doc (amd64)	15m 25s
cargo examples (amd64)	13m 36s
Run sqllogictest with Postgres runner	3m 38s
verify benchmark results (amd64)	12m 27s
check Cargo.toml formatting	2m 51s
clippy	5m 39s
cargo test hash collisions (amd64)	16m 53s
check configs.md and ***_functions.md is up-to-date	3m 7s
cargo test pyarrow (amd64)	2m 47s
	8h 10m 5s

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