fix: formula division for mysql

[wingkwong]

Change Summary

ref: #4527

• mark CallExpression on pt.right for division
• cast char first before casting as double for FLOAT

For select option, the data type would be enum . The existing SQL would produce the wrong result.

-- existing
(CAST(`t1` as DOUBLE)) / `t2`

-- PR
CAST(CAST(`t1` as CHAR) AS DOUBLE) / CAST(CAST(`t2` as CHAR) AS DOUBLE)

Change type

• feat: (new feature for the user, not a new feature for build script)
• fix: (bug fix for the user, not a fix to a build script)
• docs: (changes to the documentation)
• style: (formatting, missing semi colons, etc; no production code change)
• refactor: (refactoring production code, eg. renaming a variable)
• test: (adding missing tests, refactoring tests; no production code change)
• chore: (updating grunt tasks etc; no production code change)

Test/ Verification