Bases de datos

\d. Muestra todas las columnas de la tabla y el tipo de datos de cada una de ellas.
\q. Sale de psql y vuelve al terminal.
· SELECT Incluye los datos que se solicitan en la consulta.
· FROMDetermina la tabla o tablas de la que se tomaran los datos.
· WHERE Indica un predicado que deben cumplir las columnas de la consulta.
= > <
LIKE.
· ORDER BY Indica el orden por el cual extraeremoslos datos solicitados.
ASC Orden ascendente.
DESC Orden descendente.


1. SELECT * FROM emp;
2. SELECT * FROM dept;
3. SELECT * FROM emp WHERE job LIKE '$CLERK$';
4. SELECT * FROM empWHERE job LIKE '$CLERK$' ORDER BY ename;
5. SELECT * FROM emp WHERE job LIKE '$CLERK$' ORDER BY ename DESC;
6. SELECT ename sal ename FROM emp;
7. SELECT dname FROM empno;
8. SELECT dname FROM empnoORDER BY dname;
9. SELECT dname FROM empno ORDER BY loc;
10. SELECT dname FROM empno ORDER BY DESC loc;
11. SELECT job ename FROM emp ORDER BY sal;
12. SELECT job ename FROM emp ORDER BY job, sal;13. SELECT job, ename, sal FROM emp ORDER BY sal ASC, job DESC;
14. SELECT sal, comm FROM emp WHERE dept=30;
15. SELECT sal, comm FROM emp WHERE dept=30 ORDER BY comm;
16a. SELECT comm FROM emp;16b. SELECT DISTINCT comm FROM emp
17. SELECT DISTINCT ename, comm FROM emp
18. SELECT DISTINCT ename, sal FROM emp;
19. SELECT DISTINCT deptno, comm FROM emp;
20. SELECT ename, sal+1000 FROM empWHERE deptno=30;
21. SELECT ename, sal+1000 AS NUEVO_SALARIO FROM emp WHERE deptno=30;
22. SELECT ename FROM emp WHERE comm>sal/2;
23. SELECT ename FROM emp WHERE comm7500;
26. SELECT ename FROMemp WHERE ename>'%j%';
27. SELECT sal, comm, sal+comm AS salario_total FROM emp WHERE comm is not null OR comm0 ORDER BY empno;
28. SELECT sal, comm, sal+comm AS salario_total FROM emp WHERE comm isnull OR comm=0 ORDER BY empno;
29. SELECT ename FROM emp WHERE sal>1000 AND mgr=7698
30. SELECT ename FROM emp WHERE NOT sal>100 AND NOT mgr=7698;
31. SELECT comm*100/sal AS Porcentaje FROM emp...