1. Arrays (6625/-)
2. Assignment statements (4302/-)
3. Associative Arrays (4756/-)
4. Case-Sensitivity (5341/-)
5. Comments (6139/-)
6. Common string constants (4424/-)
7. Create thumbnails using PHP (12107/-)
8. Dates (5976/-)
9. End of statement (4193/-)
10. Equality (3416/-)
11. For loops (4153/-)
12. Get a user's IP address (10374/-)
13. HTML encoding functions (6695/-)
14. If statements (5276/-)
15. Loosely Typed Variables (3805/-)
16. MySQL - 'INSERT..SELECT' copies data from a SELECT into a table (12181/-)
17. MySQL - Adding or Subtracting days (8427/-)
18. MySQL - Components of a date (5723/-)
19. MySQL - Concatenate strings (48755/-)
20. MySQL - Conditional values (17540/-)
21. MySQL - CREATE a new table (6463/-)
22. MySQL - Delete (12143/-)
23. MySQL - DROP an unwanted table (5109/-)
24. MySQL - Explicitly enter a NULL (4407/-)
25. MySQL - Find the Insert ID (6284/-)
26. MySQL - Finding a substring in a string (15942/-)
27. MySQL - Finding out your tables (4311/-)
28. MySQL - Format dates (10886/-)
29. MySQL - Formatting numbers to two decimal places (16588/-)
30. MySQL - Get the 11th to the 20th rows of the Squeek table - by UserName (4962/-)
31. MySQL - Get the date and time right now (9095/-)
32. MySQL - Get the first 10 rows of the Squeek table (5017/-)
33. MySQL - Insert (14210/-)
34. MySQL - Insert a date (22916/-)
35. MySQL - Joining two tables (11760/-)
36. MySQL - Match a range of dates (9197/-)
37. MySQL - Match a specific date (4916/-)
38. MySQL - Replace a NULL with a specific value (12873/-)
39. MySQL - Select - including strtolower() (12596/-)
40. MySQL - Select random row (27550/-)
41. MySQL - SELECT within SELECT (28922/-)
42. MySQL - Substring: Extracting part of a string (23524/-)
43. MySQL - Update (12000/-)
44. MySQL - uppercase / lowercase (14966/-)
45. MySQL - What are the columns of the Squeek table? (3986/-)
46. Need to declare variables? (5228/-)
47. PHP - Random Number (16286/-)
48. PHP - Sending Email (9914/-)
49. Print 1 to 10 on a web page (4887/-)
50. Regular Expressions (4801/-)
51. Script Tags (4794/-)
52. Sending HTML to Browser (3811/-)
53. String Concatenation (9685/-)
54. String Evaluation (4865/-)
55. Strings (3795/-)
56. Switch/Case (4237/-)
57. True and False (3512/-)
58. Variables (3311/-)
59. While statements (3767/-)

== true if equal
!= not equal

=== true if equal & same type
!== not identical
Note that some functions can return 0 or false (false is typically used to indicate failure) depending on the context. For these functions, you will need to use === to determine whether 0 or false was returned. Some problematic functions: strpos, strrpos, strstr, stristr, strrchr