SQL Keywords
SQL keywords are case insensitive. So the keyword SELECT and select will behave in the same way. Let’s look at some of the commonly used SQL keywords.
- ALTER TABLE: ALTER TABLE is used for altering column of a table.
12345ALTER TABLEtable_nameADD column datatype;
Output: On execution of this command a column will get added to the table table_name. - AND: AND is an sql operator which is used for adding multiple condition. If the conditions are satisfied by a row. It will be part of the result set.
123456SELECT column_nameFROM table_nameWHERE column1 = value1AND column2 = value2;
Output: On execution of this command, if column1 is equal to value1 and column2 is equal to value2 then only the row will be qualified for result set. - AS: AS is used for aliasing a column or table.
1234SELECT column_name AS 'Alias'FROM table_name;
Output: On execution of this command, the result will display column_name as ‘Alias’.
- AVG: AVG is an aggregate function which will provide the average of the numeric column.
123SELECT AVG(column_name) FROM table_name;
Output: Execution of this command will provide the average of column_name. - BETWEEN: BETWEEN is an operator which is used for defining a set. The value for range can be numeric, text and date.
12345SELECT column_name(s)FROM table_nameWHERE column_name BETWEEN value1 AND value2;
Output: Execution of this command will give a result set bounded by value1 and value2. - COUNT: COUNT is a function which provides the count of the row for a column. The column should be a not null column.
123SELECT COUNT(column_name) FROM table_name;
Output: On execution of this command, the result will contain the count of the rows for column_name. - CREATE TABLE: This command is used to create table in the database. It allows to specify the name of the table along with the name a datatype of the column.
123CREATE TABLE table_name (column1 datatype, column2 datatype);
Output: Execution of this command will result in creation of table with name as table_name along with column1 and column2 as the columns of the table. - DELETE: DELETE is the command which is used for removing rows from the table
123DELETE FROM table_name WHERE column_name = value;
Output: On execution of this command the rows that will be selected based on the condition in the WHERE clause will be deleted.
- GROUP BY: GROUP BY is a clause in SQL that is only used with aggregate functions. It is used along with the SELECT statement to arrange identical data into groups.
12345SELECT COUNT(*)FROM table_nameGROUP BY column_name;
Output: Execution of this order will result in grouping the result set based on the column_name. - INNER JOIN: INNER JOIN will select records with matching values in two tables.
12345SELECT column_name FROM table_1INNER JOIN table_2ON table_1.column_name = table_2.column_name;
Output: Above command will result in rows where both tables have matching values for column_name. - INSERT: INSERT is used for adding a new row in the table.
123INSERT INTO table_name (column1, column2, column3) VALUES (value1, 'value2', value3);
Output: Execution of this command will result in addition of a new row with values corresponding to the columns. - LIKE: LIKE is an operator which is used for specifying a pattern. This operator is used along with WHERE clause.
12345SELECT column_nameFROM table_nameWHERE column_name LIKE pattern;
Output: Output will the rows that will satisfy the like pattern. - LIMIT: LIMIT is a clause which allows the restricting the result set rows to maximum number specified by the limit clause.
12345SELECT column_nameFROM table_nameLIMIT number;
Output: The resultset will be limited by the number that is provided as part of the limit clause. - MAX: MAX is a function that will return the max value from the column specified.
1234SELECT MAX(column_name)FROM table_name;
Output: The output will the maximum value specified in the column column_name. - MIN: MIN is a function that will return the min value from the column specified.
1234SELECT MIN(column_name)FROM table_name;
Output: The output will the minimum value specified in the column column_name.
- OR: OR is the operator that is used for selecting the rows based on satisfaction of either condition in WHERE clause.
123456SELECT column_nameFROM table_nameWHERE column_name = value1OR column_name = value2;
Output: Result set will contain rows where column_name value will be either value1 or value2. - ORDER BY: ORDER BY is used for sorting of columns in ascending or descending order numerically or in alphabetical order.
12345SELECT column_nameFROM table_nameORDER BY column_name ASC;
Output: On execution of the command above we will get the result set in ascending order. - LEFT JOIN, RIGHT JOIN: These will combine rows from different tables even if the join condition is not met. Every row in the left/right table is returned in the result set, and if the join condition is not met, then NULL values are filled in the columns from the left/right table.
12345SELECT column_name(s) FROM table_1LEFT JOIN table_2ON table_1.column_name = table_2.column_name;
Output: Execution of the command above will result in rows from the table_1 along with rows which satisfies the condition from table_2
12345SELECT column_name(s) FROM table_1RIGHT JOIN table_2ON table_1.column_name = table_2.column_name;
Output: Execution of the command above will result in rows from the table_2 along with rows which satisfies the condition from table_1. - ROUND: ROUND is a function that rounds of the number specified in the column based on the integer that is specified as part of the function.
1234SELECT ROUND(column_name, integer)FROM table_name;
Output: The output of the command will result in rounding up the number based on the integer that is provided as part of the function. - SELECT: SELECT is used to fetch the data from the data base.
123SELECT column_name FROM table_name
Output: On execution of this command the result set will contain rows for column column_name. - SELECT DISTINCT: SELECT DISTINCT is used for retrieving distinct values from the column that is specified.
123SELECT DISTINCT column_name FROM table_name;
Output: On execution of the command above the result set will only contain the unique values from the column column_name. - SUM: SUM is a function will provides the total value of a column which is numeric.
1234SELECT SUM(column_name)FROM table_name;
Output: Execution of this command will result in the total of all the row that are part of the column column_name. - UPDATE: UPDATE is used for updating values of a row of a table.
12345UPDATE table_nameSET some_column = some_valueWHERE some_column = some_value;
Output: Execution of this command will result in updating the row that will satisfy the condition in the where clause. - WHERE: WHERE is used for specifying the condition that should be satisfied for selecting the row to be part of the result set.
12345SELECT column_nameFROM table_nameWHERE column_name operator value;
Output: The output of this command will result in the rows that are satisfying the where clause.
That’s all for a quick roundup on mostly used SQL keywords.
Reference: Oracle SQL Reserved Words List