This lesson lists and explains all standard SQL keywords, including those not supported in our playground environment. Unsupported features are clearly marked so users know what to expect.
SQL Keywords Table Structure and Constraints
Keyword Description Playground Support Notes ADDAdds a column to an existing table ADD CONSTRAINTAdds a constraint to an existing table ALTERModifies table structure (columns, types) ALTER COLUMNChanges a column’s data type or properties ALTER TABLEAdds, deletes, or modifies columns CHECKLimits the value range of a column COLUMNUsed with ALTER TABLE to reference a column CONSTRAINTUsed to define a rule for a column or table DEFAULTSets a default value for a column CREATE TABLE, but behavior may varyDROP COLUMNDeletes a column from a table DROP CONSTRAINTRemoves constraints like PRIMARY KEY, UNIQUE, etc. NOT NULLEnsures a column cannot have NULL values PRIMARY KEYUniquely identifies records in a table FOREIGN KEYLinks a column to another table’s key UNIQUEEnsures all values in a column are different
SQL Keywords Data Definition (DDL)
Keyword Description Playground Support Notes CREATECreates tables, views, indexes, etc. CREATE DATABASECreates a new database CREATE INDEXAdds an index to improve query speed CREATE OR REPLACE VIEWUpdates or replaces a view CREATE PROCEDUREDefines a stored procedure CREATE TABLECreates a new table CREATE UNIQUE INDEXCreates an index that ensures unique values CREATE VIEWDefines a virtual table DATABASERefers to the current or another database DROPDeletes tables, views, databases, etc. DROP DATABASEDeletes an entire database DROP DEFAULTRemoves a default constraint DROP INDEXDeletes an index DROP TABLEDeletes a table DROP VIEWDeletes a view EXECExecutes a stored procedure PROCEDURERefers to stored procedures TABLERefers to a table for DDL or DML commands TRUNCATE TABLEDeletes all rows, keeps structure
SQL Keywords Data Manipulation (DML)
Keyword Description Playground Support Notes INSERT INTOAdds new rows to a table INSERT INTO SELECTCopies rows from one table to another UPDATEModifies existing records SETAssigns values in an UPDATE DELETERemoves rows from a table VALUESProvides values for an INSERT
SQL Keywords Query and Filtering
Keyword Description Playground Support Notes SELECTRetrieves data from one or more tables SELECT DISTINCTReturns unique values only SELECT INTOCreates a new table from a SELECT SELECT TOPLimits rows returned (T-SQL) LIMIT insteadWHEREFilters rows by condition ANDCombines conditions (both must be true) ORCombines conditions (either can be true) NOTNegates a condition INChecks if a value is in a list BETWEENChecks if a value is within a range LIKESearches for a pattern using wildcards IS NULLTests for NULL values IS NOT NULLTests for non-NULL values EXISTSTests for subquery existence CASEConditional logic in queries ASRenames a column or table with an alias
SQL Keywords Joins and Subqueries
Keyword Description Playground Support Notes JOINCombines rows from two or more tables INNER JOINReturns matching rows in both tables LEFT JOINReturns all from left table + matched right RIGHT JOINReturns all from right table + matched left FULL OUTER JOINReturns all rows with matches in either table OUTER JOINGeneral outer join syntax ANYReturns true if any subquery values match ALLReturns true if all subquery values match
SQL Keywords Aggregates and Grouping
Keyword Description Playground Support Notes GROUP BYGroups rows for aggregate functions HAVINGFilters groups (used with aggregates) ORDER BYSorts result set by one or more columns ASCSorts in ascending order DESCSorts in descending order
SQL Keywords Set Operations
Keyword Description Playground Support Notes UNIONCombines SELECT results, no duplicates UNION ALLCombines SELECT results, includes duplicates
SQL Keywords Limits and Rows
Keyword Description Playground Support Notes LIMITLimits the number of returned rows TOPLimits rows (T-SQL style) LIMIT insteadROWNUMOracle-style row limiting
SQL Keywords Labs
Supported
Partially supported (some constraint types may not work)
Not supported in our playground