Results for “Lifecycle & observable data”
Small, practical examples. Search by task or narrow things down below.
Count rows satisfying separate conditions
Postgres: SUM over CASE expressions calculates several conditional counts in one scan.
Postgres✓ Tested
Count rows satisfying separate conditions
SQLite: SUM over CASE expressions calculates several conditional counts in one scan.
SQLite✓ Tested
Count the rows in a table
SQL: COUNT(*) includes every row, including rows with NULL columns.
SQL✓ Tested
Count the rows in a table
SQL Server: COUNT(*) includes every row, including rows with NULL columns.
SQL Server✓ Tested
Create a native disclosure
Use details and summary to show optional HTML content without JavaScript.
HTML✓ Tested
Create a table and insert its first row
SQL: Define column types and a primary key, then insert one row using an explicit column list.
SQL✓ Tested
Create a table and insert its first row
SQL Server: Define column types and a primary key, then insert one row using an explicit column list.
SQL Server✓ Tested
Create an index for an equality filter
SQL: A nonunique index can support lookups on a frequently filtered column.
SQL✓ Tested
Create an index for an equality filter
SQL Server: A nonunique index can support lookups on a frequently filtered column.
SQL Server✓ Tested
Create an index for an equality filter
Postgres: A nonunique index can support lookups on a frequently filtered column.
Postgres✓ Tested
Create an index for an equality filter
SQLite: A nonunique index can support lookups on a frequently filtered column.
SQLite✓ Tested
Create an index matching filter and ordering columns
SQL: Place the equality-filter column before the ordering column in this composite index.
SQL✓ Tested