Important SQL terms and its meaning - Part 3

Important SQL terms and its meaning - Part 3

  1. DELETE - This is your tool for deleting rows of data from your table. Use it with a WHERE clause to precisely pinpoint the rows you want to remove
  2. DISTINCT - Returns each unique value only once, with no duplicates.
  3. DROP TABLE - Lets you delete a table if ou make a mistake, but you'll need to do this before you start using INSERT statements which let you add the values for each column.
  4. EQUIJOIN and NON-EQUIJOIN - Both are inner joins. The equijoin returns rows that are equal, and the non-equijoin returns any rows that are not equal.
  5. Escape with ' and \ - Escale out apostrophes in your text data with an extra apostrophe or backslash in front of it.
  6. EXCEPT - Use this keyword to return only values that are in the first query BUT NOT in the second query.
  7. FIRST NORMAL FORM(1NF) - Each row of data must contain atomic values, and each row of data must have a unique identifier.
  8. Foreign Key - A column in a table that references the primary key of another table.
  9. GRANT - This statement lets you control exactly what users can do to tables and columns based on the privileges you give them.
  10. GROUP BY- Consolidates rows based on a common column.

No alt text provided for this image


要查看或添加评论,请登录

社区洞察

其他会员也浏览了