Is SQL syntax case sensitive?

The SQL Keywords are case-insensitive (SELECT, FROM, WHERE, etc), but are often written in all caps. However in some setups table and column names are case-sensitive. MySQL has a configuration option to enable/disable it. Usually case-sensitive table and column names are the default on Linux MySQL and case-insensitive used to be the default on Windows, but now the installer asked about this during setup. For MSSQL it is a function of the database's collation setting.

Here is the MySQL page about name case-sensitivity

Here is the article in MSDN about collations for MSSQL

This isn't strictly SQL language, but in SQL Server if your database collation is case-sensitive, then all table names are case-sensitive.

The SQL92 specification states that identifiers might be quoted, or unquoted. If both sides are unquoted then they are always case-insensitive, e.g. table_name == TAble_nAmE.

However quoted identifiers are case-sensitive, e.g. "table_name" != "TAble_naME". Also based on the spec if you wish to compare unqouted identifiers with quoted ones, then unquoted and quoted identifiers can be considered the same, if the unquoted characters are uppercased, e.g. TABLE_NAME == "TABLE_NAME", but TABLE_NAME != "table_name" or TABLE_NAME != "TAble_NaMe".

Here is the relevant part of the spec (section 5.2.13):

     13)A <regular identifier> and a <delimited identifier> are equiva-
        lent if the <identifier body> of the <regular identifier> (with
        every letter that is a lower-case letter replaced by the equiva-
        lent upper-case letter or letters) and the <delimited identifier
        body> of the <delimited identifier> (with all occurrences of
        <quote> replaced by <quote symbol> and all occurrences of <dou-
        blequote symbol> replaced by <double quote>), considered as
        the repetition of a <character string literal> that specifies a
        <character set specification> of SQL_TEXT and an implementation-
        defined collation that is sensitive to case, compare equally
        according to the comparison rules in Subclause 8.2, "<comparison
        predicate>".

Note, that just like with other parts of the SQL standard, not all databases follow this section fully. PostgreSQL for example stores all unquoted identifiers lowercased instead of uppercased, so table_name == "table_name" (which is exactly the opposite of the standard). Also some databases are case-insensitive all the time, or case-sensitiveness depend on some setting in the DB or are dependent on some of the properties of the system, usually whether the filesystem is case-sensitive or not.

Note that some database tools might send identifiers quoted all the time, so in instances where you mix queries generated by some tool (like a CREATE TABLE query generated by Liquibase or other DB migration tool), with hand made queries (like a simple JDBC select in your application) you have to make sure that the cases are consistent, especially on databases where quoted and unquoted identifiers are different (DB2, PostgreSQL, etc.)