If we look it up in the dictionary: literals are meanings. Description of something, in the form of text. In MySQL, Oracle, SQL Server, or any other database, a literal is the content of a variable, or simply a value offered for a comparison.
sqlCopyEditSET var_Name = 'ALEXANDRE';
In the example above, we are assigning the literal ALEXANDRE to the variable var_Name. We can say that the content (or meaning) of var_Name is ALEXANDRE.
Ah! I get it!!! Everything between quotes is a literal. Not so fast. The analogy is good, but imperfect.
sqlCopyEditSET var_I_like_to_move_it_move_it = FALSE;
SET @var_Price = 10;
SET @Qtty = 3;
SET @Total = @var_Price * @Qtty;
FALSE (0) is a literal assigned to var_I_Like_To_Move_it_Move_it. Although my kids love Madagascar, and I like King Julian, I don’t like to dance. So, FALSE (0 in MySQL) describes the content of the variable to which it was assigned.
10 is the literal assigned to the integer variable @var_Price. Likewise, 3 tells the value of the variable @Qtty. The computation (calculation) of the literals contained in the environment variables @var_Price and @Qtty describes the environment variable @Total.
So, a literal can be of any type: characters (string), numbers, dates, booleans, or even binary.
sqlCopyEditSELECT * FROM tab_1 WHERE data_compra >= '2020-01-01';
The literal ‘2020-02-01’ was used to establish a comparison with the purchase date, making it possible to filter data from the tab_1 table.
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