SQL cheat sheet
Standard SQL that works in PostgreSQL, MySQL, SQLite and SQL Server, with small differences noted. Click a query to copy it.
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Reading data
- Every column of every row
- Only some columns
- Each value once
- Rename a column in the result
- Number of rows
Filtering
- Equal to (<> or != for not equal)
- Combine conditions (OR, NOT too)
- In a range, including both ends
- Matches any value in a list
- Starts with “An” (% any text, _ one character)
- Empty value (IS NOT NULL for filled)
Sorting and limiting
- Newest first (ASC for oldest first)
- Sort by several columns
- Only the first 10 rows (SQL Server: SELECT TOP 10)
- Rows 21–30, for paging
Joins
- Rows that match in both tables (INNER JOIN)
- All users, with orders when they have any
- After a LEFT JOIN: users without orders
- All rows from both tables (not in MySQL)
Grouping
- Count per group
- Other totals per group
- Filter groups (WHERE filters rows before grouping)
Changing data
- Add a row
- Change rows (always add WHERE!)
- Delete rows (always add WHERE!)
- Do several changes together (ROLLBACK to cancel)
Tables and indexes
- Create a table (PostgreSQL types)
- Add a column
- Speed up searches on a column
- Delete a table and all its data
Handy extras
- First value that isn’t empty
- If/else inside a query
- Name a sub-query (CTE) to keep things readable
- Stack results, without duplicates (UNION ALL keeps them)