Results for “read rows”
Small, practical examples. Search by task or narrow things down below.
Check for a hashtable key before reading it
PowerShell: ContainsKey distinguishes a missing key from a key whose value happens to be null.
PowerShell✓ Tested
Check whether a file is already sorted
Linux Commands: Use sort -C for a quiet status check that does not rewrite the file.
Linux Commands✓ Tested
Check whether a future is ready without blocking
C++: A zero-duration wait reports timeout until the producer sets a value.
C++✓ Tested
Check whether a range is already sorted
C++: is_sorted reports ordering without modifying the input.
C++✓ Tested
Copy selected rows into another table
SQL: INSERT SELECT performs a set-based copy with an explicit destination column list.
SQL✓ Tested
Copy selected rows into another table
SQL Server: INSERT SELECT performs a set-based copy with an explicit destination column list.
SQL Server✓ Tested
Copy selected rows into another table
Postgres: INSERT SELECT performs a set-based copy with an explicit destination column list.
Postgres✓ Tested
Copy selected rows into another table
SQLite: INSERT SELECT performs a set-based copy with an explicit destination column list.
SQLite✓ Tested
Count rows per category
Aggregate rows sharing the same category.
GROUP BY✓ Tested
Count rows satisfying separate conditions
SQL: SUM over CASE expressions calculates several conditional counts in one scan.
SQL✓ Tested
Count rows satisfying separate conditions
SQL Server: SUM over CASE expressions calculates several conditional counts in one scan.
SQL Server✓ Tested
Count rows satisfying separate conditions
Postgres: SUM over CASE expressions calculates several conditional counts in one scan.
Postgres✓ Tested