SQL(oh)				     LOCAL			       SQL(oh)

sql - queries and usage.

QUERIES
     -	 select * will show all fields
     -	 select distinct means it will only show unique records

SELECT
     Select all records from table
	    : select * from TABLE;
     Select unique records
	    : select distinct * from TABLE;
     Select all records, showing only specified fields
	    : select FIELD1, FIELD2 from TABLE;
     Count records from table
	    : select count(1) from TABLE;
     Select only records matching condition
	    : select * from TABLE where FIELD = VALUE;

   Multiple tables
     -	 Select all record matching multiple conditions :
	       select * from TABLE where FIELD1 = VALUE1 and FIELD2 = VALUE2;
     -	 Select all matching records from multiple tables :
	       select * from TABLE1, TABLE2 where TABLE1.FIELD1 =
	       TABLE2.FIELD2;

   alias
     -	 Set table alias to simplify use:
	       select * from TABLE1 ALIAS1;
     -	 Use the alias when selecting:
	       select T1.FIELD1, T1.FIELD2 from TABLE1 T1;

GROUPING
     -	 Select record count by group:
	       select FIELD, count(FIELD) from TABLE group by FIELD;
     -	 Select record count by group where count is greater than 1 :
	       select FIELD, count(FIELD) from TABLE group by FIELD having
	       count(FIELD) > 1;
     Grouping functions include: count, avg, min, max, sum. Example: select
     FIELD1, sum(FIELD2) from TABLE group by FIELD1;

LIMITS
     Limit displayed records
	    : select * from TABLE limit 10;
     Select 10 records starting from the 5th record
	    : select * from TABLE limit 10 offset 5;

JOINS
     Joins data from multiple tables using [INNER] JOIN. JOIN implies INNER
     JOIN.
     select
     T1.FIELD1, T1.FIELD2,
     T2.FIELD1, ALIAs2.FIELD2
     from TABLE1 T1
     join TABLE2 T2 on T2.FIELD = T1.FIELD;

   outer join
     Displays records matching any of the joined tables. Possible values are
     [LEFT|RIGHT|FULL] [OUTER] JOIN. Specifying OUTER is not necessary when
     using LEFT, RIGHT, FULL as it's implied.

   left
     Displays all records from the left table and matching records from the
     right table. Right is similar only showing records from right and
     matching from left.
     select * from TABLE1 T1
     right join TABLE2 T2 on T2.FIELD = T1.FIELD;

   full
     Shows all records from both tables.

SEE ALSO
     sqlite3(oh) , mysql(oh)

AUTHORS
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linux , OpenBSD 7.8 |
		    Created:2026-03-23|Updated:2026-03-25|	       SQL(oh)